Final Report of the Cosmetic Ingredient Review Expert Panel

Safety Assessment of Coal Tar

March 16, 2004

The 2004 Cosmetic Ingredient Review Expert Panel members are: Chairman, Wilma F. Bergfeld, M .D., F.A.C.P.; Donald

V. Belsito, M.D.; Curtis D. Klaassen, Ph.D.; James G. M arks, Jr ., M.D ., Ronald C. Shank, Ph.D.; Thomas J. Slaga, Ph.D.;

and Paul W. Snyder, D.V.M., Ph.D. The CIR Director is F. Alan Andersen, Ph.D. This final safety assessment was

prepared by M elody A. Chen, Scientific Analyst and Writer.

Cosmetic Ingredient Review1101 17th Street, NW, Suite 310 " Washington, DC 20036-4702 " ph 202.331.0651 " fax 202.331.0088 " cirinfo@cir-safety.org

Copyright 2004

Cosmetic Ingredient Review

1101 17th Street, NW, Suite 310

Washington, DC 20036

1

Final Safety Assessment of Coal Tar

Abstract: Coal Tar is a semisolid byproduct obtained in the destructive distillation of bituminous coal which functions in

cosmetic products as a cosmetic biocide and denaturant — antidandruff agent is also listed as a function, but this is considered

an over-the-counter (OTC) drug use. Coal Tar is a nearly black, viscous liquid, heavier than water, with a naphthalene-like odor

and a sharp burning taste, produced in coking ovens as a byproduct in the manufacture of coke. Crude Coal Tar is composed

of 48% hydrocarbons, 42% carbon, and 10% water. In 2002, Coal Tar was reported to FDA to be used in four formulations,

all of which appear to be OT C drug products. Coal Tar is monographed by the Food and Drug Administration as Category I

(safe and effective) for over-the-counter drug ingredient for use in the treatment of dandruff, seborrhoea, and psoriasis. Coal

Tar is absorbed through through the skin of animals and humans and is systemically distributed. In short term studies, mice

fed Coal Tar in their diet found their diet unpalatable, but no adverse effects were reported other than weight loss; rats injected

with Coal Tar experienced malaise in one study and decreased water intake and increased liver weights in another; rabbits

injected with Coal Tar residue experienced eating avoidance, respiratory difficulty, sneezing, and weight loss. In a subchronic

neuro toxicity study using mice, a mixture of phenols, cresols, and xylenols at concentrations approximately equal to those

expected in Coal Tar extracts produced regionally selective effects, with a rank order of striatum > cerebellum > cerebral cortex.

Coal Tar applied to the backs of guinea pigs increases ep idermal thickness. Painting female rabbits with tar decreases the

absolute and relative weights of the ovaries and decreased the number of interstitial cells in the ovary. Four therapeutic Coal

Tar preparations used in the treatment of psoriasis screened using the Ames test were mutagenic. Urine and blood from patients

treated with Coal Tar were geno toxic in bacterial assays. Coal Tar was genotoxic in a mammalian genotoxicity assay and

induced DNA adducts in various tissue types. Chronic exposure of mice significantly decreased survival and liver neoplasms

were seen in a significant dose-related trend; in other studies using mice lung tumors and perianal skin cancers were found. Coal

Tar was comedogenic in three small clinical studies. Folliculitis is associated with the prolonged use of some tars. Several

published reports describe cases of contact sensitivity to Coal Tar. Po lycyclic aromatic hydrocarbons which make up Coal Tar

are photosensitizers and cause phototoxicity by an oxygen dependent mechanism. A retrospective study of the reproductive

toxicity of Coal Tar in humans compared exposed women to controls and found little difference in spontaneous abortion and

congenital disorders. Cancer epidemiology studies of patients who have received Coal Tar therapy of one form or other have

failed to link treatment with an increase in the risk of cancer. While the CIR Expert Panel believes that Coal Tar use as an

antidandruff ingredient in OTC drug preparations is adequately addressed by the FDA regulations, the Panel also believes that

the appropriate concentration of use of Coal Tar in cosmetic formulations should be that level that does not have a biological

effect. Additional data needed to make a safety assessment include product types in which Coal Tar is used (other than as an

OT C drug ingredient), use concentrations, and the maximum concentration that does not induce a biological effect.

INTRODUCTION

Coal Tar (CAS No. 8007-45-2) is a thick liquid or semi-solid

obtained as a byproduct in the destructive distillation of

bituminous coal. In the United States, Coal Tar may be used

as an active ingredient (treatment of dandruff, seborrhoea, and

psoriasis) in OT C drug products. Coal Tar is listed as an

antidandruff agent, cosmetic biocide, and denaturant in

cosmetics in the International Cosmetic Ingredient Dictionary

and Handbook (Gottschalck and M cEwen, 2004).

CHEMISTRY

DEFINITION AND STRUCTURE

According to International Agency for Research on Cancer

(IARC, 1985) and the Environmental Protection Agency

(EPA, 1994), crude Coal Tar is composed of 48%

hydrocarbons, 42% carbon, and 10% water. It is composed of

approximately 10,000 compounds, of which about 400 have

been identified. One hundred of these 400 compounds are

polycyclic aromatic hydrocarbons (PAHs) only 17 of which

have been chemically and toxicologically characterized.

2

Synonyms for Coal Tar include Picis Carbonis and Pix

Carbonis, (Budavari, 1989; Lewis, 1993; RTECS, 2001).

Jackson (2003) stated that Crude Coal Tar is refined or

processed for use in over-the-counter drug products by alcohol

extraction (USP coal tar) or vegetable o il solubilization. There

are also coal tars refined by patented and proprietary filtration

and solubilization processes which are also used in over-the-

counter drug products.

The USP does not resolve whether products labeled as Coal

Tar are refined or crude, stating only that such material may

be processed further, while products labeled as Coal Tar

topical solution are clearly refined (Committee on Revision of

the United States Pharmacopeial Convention, 1995).

PHYSICAL AND CHEM ICAL PROPERTIES

Coal Tar is a nearly black, viscous liquid, heavier than water,

with a naphthalene-like odor and a sharp burning taste

(Gennaro, 1990). The composition of Coal Tar is variable,

but generally it consists of 2 to 8% light oils (benzene,

toluene, xylene); 8 to 10% middle oils (phenols, cresols, and

naphthalene); 8 to 10% heavy o ils (naphthalene and

derivatives); 16 to 20% anthracene oils (mostly anthracene);

and about 50% pitch (Gosselin e t al., 1984). Coal Tar is

“practically insoluble” in water; however “all or almost all”

dissolves in benzene or nitrobenzene (Budavari, 1989).

METHOD OF M ANUFACTURE

Coal Tar is produced in coking ovens as a byproduct in the

manufacture of coke (see Figure 1). In this process, coal is

subjected to destructive distillation and is transformed into an

amorphous mass of coke, which in turn is used in the

manufacture of steel. The gases produced are condensed,

forming a liquid. Upon removal of ammonia, a black viscous

product, crude Coal Tar, is left. Crude Coal Tar may be

heated at various temperatures to yield fractional distillates as

shown in Figure 2 (Lin and Moses, 1985).

Lerner and Lerner (1960) noted that the term “crude coal tar”

was not very specific. For example, when crude Coal Tar is

ordered without further specification in the eastern part of the

United states, it is prepared from bituminous (soft) coal,

whereas when it is ordered on the west coast, it comes from

the oils of natural gas. Some commercial dermatologic tars are

derived from anthracite (hard) coal.

According to the Code of Federal Regulations

(21CFR358.703), the Coal Tar used for medicinal purposes is

“obtained as a byproduct during the destructive distillation of

bituminous coal at temperatures in the range of 900 deg. C to

1,100 deg. C. It may be further processed using either

extraction with alcohol and suitable dispersing agents and

maceration times or fractional distillation with or without the

use of suitable organic solvents”.

ANALYTICAL METHODS

Crude Coal Tar, refined Coal Tar, and over-the-counter drug

products containing Coal Tar are analyzed by one of two

methods: high pressure liquid chromatography with either UV

or fluorescence detection (HPLC/UV, HPLC/FD), and gas

chromatography/mass spectroscopy (GC/MS) (EPA, 1994;

Litofsky, 1999).

Figure 1. Derivation of crude Coal Tar (Lin and Moses,

1985).

Figure 2. Fractional distillation of Coal Tar (Lin and

Moses, 1985).

3

USE

CO SM ETIC

As noted earlier, the International Cosmetic Ingredient

Dictionary and Handbook (Gottschalck and McEwen, 2004)

gives the functions of Coal Tar in cosmetic products as a

cosmetic biocide and denaturant — antidandruff agent is also

listed as a function, but this is considered an over-the-counter

(OTC) drug use. For more information on the OTC drug use,

see the NON-COSM ETIC use section.

Industry reports to the Food and Drug Administration (FDA)

give current categories with products containing Coal Tar

(FDA, 2002), but as noted above and in Table 1, these uses

are over-the-counter (OTC) drug uses in which coal tar

functions as an antidandruff ingredient.

According to the Bureau of Alcohol, Tobacco, and Firearms

regulations in the Code of Federal Regulations (CFR), 10

pounds of Coal Tar may be added as a denaturant to 100

gallons of ethanol to make SD Alcohol 38-B, which has uses

listed as hair and scalp preparations; lotions and creams;

deodorants; perfumes and perfume tinctures; toilet waters and

colognes; dentifrices; mouthwashes; shampoos; and soap and

bath preparations (27CFR21.65). As 1 gallon of ethano l =

6.59 pounds, the approximate maximum concentration of use

for Coal Tar used as a denaturant is 10 pounds Coal Tar/659

pounds of ethanol = 1.5% (CTFA 2002).

Currently, there appear to be no uses of Coal Tar as a

denaturant or as a cosmetic biocide.

In Europe, Coal Tar is in the list of substances which must not

form part of the composition of cosmetic products (EEC

Cosmetics Directive, 1999). Coal Tar is not included on the

list of prohibited ingredients that are marketed in Japan

(Ministry of Health, Labor, and W elfare [MHLW ], 2001a)

or on the list of restricted ingredients for cosmetic products

that are marketed in Japan (MHLW , 2001b).

Coal Tar is used in shampoos as a keratolytic or exfoliative in

the treatment of dandruff (Wilkinson and Moore, 1982).

According to the International Cosmetic Ingredient Dictionary

and Handbook, Coal Tar functions as an antidandruff agent,

cosmetic biocide, and denaturant in cosmetics (Gottschalck

and McEwen, 2004).

NO N-COSMETIC

Coal Tar is monographed by the FDA as a Category I (safe

and effective) for over-the-counter drug ingredient for use in

the treatment of dandruff, seborrhoea, and psoriasis (FDA,

1982; 1986; 1991). FDA regulations specify the

concentration for Coal Tar for external drug products in the

control of dandruff at 0.5 to 5 percent (21CFR358.710). FDA

re-reviewed Coal Tar in 2001 in response to a citizens

petition. This review, including more recent epidemiology

studies, confirmed Coal Tar as a Category I (Safe and

Effective) OTC drug ingredient (FDA, 2001a; FDA, 2001b).

Therefore, while the International Cosmetic Ingredient

Dictionary and Handbook (Gottschalck and McEwen, 2004)

gives a function of Coal Tar in cosmetics as an antidandruff

agent, industry reports of Coal Tar use in cosmetics are

actually in OTC preparations (as an antidandruff agent) at

concentrations from 0.06 - 7% (CTFA, 2002).

Coal Tar is used in the treatment of chronic skin diseases, such

as psoriasis , often with ultraviolet radiation. It reportedly

suppresses hyperplasia by decreasing ep idermal synthesis of

DNA (Gennaro, 1990).

Coal Tar is also used for waterproof coatings, wood

impregnation, road surfaces, and as a chemical feedstock for

the production of benzene, toluene, xylene, phenol, etc.

(L’Epee et al., 1983).

Table 1. Coal Tar Product Formulation and Concentration of Use Data

Product Category (Total number of Formulations in Category, FDA, 2002)

Formulations containing Coal Tar(FDA 2002)

Current concentration of use (CTFA 2002)

Bath preparations

Bath Oils, Tablets, and Salts (143) - .06 - 5%*

Hair preparations (non-coloring)

Shampoos (884) 3* 1 - 7%*

Tonics, Dressings, etc. (598) 1* 5%*

Total uses/ranges for Coal Tar 4* 0.06 - 7%*

* Over-the-counter (OTC) drug uses (treatment of dandruff, seborrhoea, and psoriasis); There are no reported cosmetic uses of coal tar as a cosmeticbiocide or denaturant.

4

GENERAL BIOLOGY

ABSORPTION, DISTRIBUTION, M ETABO LISM,

EXCRETION

The information on absorption, distribution, metabolism, and

excretion of Coal Tar is gleaned from studies for which

gathering these data were not the purpose of the study. Studies

involving various animal species and humans are described.

In many cases penetration of Coal Tar through the stratum

corneum was detected by measuring enzyme induction rather

than Coal Tar or one of its constituents, e.g. aryl hydrocarbon

hydroxylase (AHH) induction.

Mice

Das et al. (1985) irradiated SKH hairless mice with UVB to

induce squamous cell carcinoma (SCC). Mice were given a

single topical application of USP Coal Tar solution (1

ml/100g) 24 hours before being killed. Coal Tar treatment

resulted in a 14-fold induction of AHH and 7-ethoxycoumarin

O-deethylase (ECD) activities.

Das et al. (1986) divided twenty four male athymic nude mice

with skin engrafted from one human specimen into three

groups of eight animals. Group 1 mice were treated topically

with 0.1 ml of Crude Coal Tar to the human grafted skin.

Group 2 received 0.1 ml of Crude Coal Tar at a site opposite

to the grafted skin. Group 3 received 0.1 ml of acetone on

both the engrafted human and mouse skin. All animals were

killed 24 hours after the application of Crude Coal Tar. The

skin was scraped, then minced and homogenized. AHH and

ECD levels were measured with a spectrophotofluorimeter and

ethoxyresorufin deethylase (ERD) levels were measured with

a spectrofluorometer.

Group 1 mice showed 3.9 and 3.5; 3.2 and 2.9; and 1.1 and

1.2 fold increases in mouse and human epidermal AHH, ERD

and ECD activities respectively. Group 2 mice showed 27 .8

and 6.4; 12.8 and 3.3; and 1.7 and 2.6 fold increases in mouse

and human epidermal AHH, ERD and ECD activities,

respectively. Topical application of Coal Tar either onto

human transplanted skin or to mouse skin also resulted in

substantial induction of hepatic and pulmonary AHH and ERD

activities (Das et al., 1986).

Weyand et al. (1991) maintained B6C3F1 mice on 0.25%

Coal Tar adulterated diets for 15 days. PAH metabolites

excreted in the urine of animals ingesting a control or

adulterated gel diet were determined by using HPLC with

fluorescence detection. 1-Hydroxypyrene (1-OH-P) was the

major fluorescent metabolite excreted by all groups of animals

maintained on a Coal Tar diet. The amount of 1-OH-P

excreted in urine paralleled the pyrene content of Coal Tar

samples.

Rats

Bickers and Kappas (1978) applied 1% Coal Tar solution

(0.05 ml) to the skin of six neonatal rats. Twenty-four hours

later, AHH activity (production of 3-OH benzo[a]pyrene

(BP)/min/mg protein) was measured in the skin and liver.

After topical application, there was a greater than 10-fold

induction of skin AHH activity compared to the controls.

Hepatic AHH activity also increased “markedly” indicating

substantial percutaneous absorption had occurred.

Bickers et al. (1982) applied 100 :l of a Coal Tar solution

(USP) to 6-8 neonatal rats. In another experiment in which

they studied maternal and prenatal enzymes 48 hours prior to

the expected date of delivery, the backs of pregnant animals

were shaved and Coal Tar solution (USP) was applied to the

shaved area. Treatment and other details are given in Tables

2 and 3 . After 24 hours, animals were killed. In each

experiment, tissues for 6 animals were pooled for single

determinations. Skin and liver were removed. The epidermis

and dermis were separated and AH H activity was assayed

spectrophotofluorometrically.

Application of Coal Tar solution to neonatal rats induced skin

and liver AHH 15- and 8- fold, respectively. AHH induction

in isolated epidermis and dermis was 10 and 18- fold over the

corresponding control values (Table 2). The authors also

tested whether the vapors from the Coal Tar solution applied

on the experimental animals might be inducing cutaneous

AHH activity in the controls. Data supporting this hypothesis

are shown in Table 4. W hen pregnant rats were treated with

Coal Tar, the skin and liver AHH activity of the mothers was

induced to a higher extent (3.8 and 4.8-fold for skin and liver

respectively) than that achieved in the fetuses (2.0 and 1.9-

fold for skin and liver respectively). In further studies, several

constituents of Coal Tar were analyzed for their ability to

induce AHH, with acridine, anthracene, and benzo[a]pyrene

reaching statistical significance as shown in Table 4 (Bickers

et al., 1982).

Mukhtar and Bickers (1982) treated neonatal rats (type

unspecified) with skin applications of 100 :l of Coal Tar

(USP) solution. Control rats were treated with acetone.

Twenty-four hours after treatment, rats were killed. AHH

activity was determined spectrophotofluorometrically.

Following topical application of Coal Tar, there was an

approximately 10-fold induction of AHH and ECD activities

in the skin. Hepatic AHH and ECD activities were induced

6.2 and 2 .9 fold, respectively. Coal Tar application also

resulted in the induction of hepatic cytosolic glutathione-S-

transferase activities in neonatal rats.

Mukhtar et al. (1986b) divided neonatal Sprague-Dawley rats

into 6 groups of 20 each. Group 1 rats, the control group,

received a single topical treatment of acetone. Group 2

received UVB alone.

5

Table 2. Effect of cutaneously applied Coal Tar on AH H in neonatal rats (Bickers et al., 1982).

TreatmentAHH (p mole 3-OH BP/min/mg protein)

Whole skin Epidermis Dermis Liver

Controla 0.24±0.03 0.35±0.02 0.42±0.03 23.22±1.41

Coal Tarb 3.69±0.42d 3.58±0.51d 7.82±0.81d 192.73±5.82d

Coal Tar fumes c 0.51±0.06d 0.62±0.04d 0.86±0.06d 39.47±1.57d

aFour-day old neonatal rats were treated with topically applied acetone (100 :l) and kept in a separate room from other experimental animals.bAnimals were treated with 100 :l Coal Tar solution (USP) 24 hours prior to sacrifice.c Animals were treated with 100 :l acetone and housed in cages adjacent to Coal Tar treated animals 24 hours prior to sacrifice. Data represents mean±SD

of 3 experiments.dResults are significantly different from respective controls (p<0.05)

Table 3. Effect of cutaneously applied Coal Tar on maternal and fetal AHH in pregnant rats (Bickers et al., 1982)

AHH (p mol 3-OH BP/min/mg protein)

Skin Liver

Control Treatment Control Treatment

Maternal a 1.01±0.11 3.82±0.26b 3.24±0.31 15.72±0.86b

Fetal a 0.24±0.01 0.47±0.03b 0.45±0.05 0.85±0.07b

a Sperm positive pregnant rats at 19 days of gestation (2 days before expected delivery) were shaved and treated with 500 :l Coal Tar solution (USP). Twenty-four hours later (16 Hours before expected delivery), mothers were killed by decapitation. Unborn rats from control and Coal Tar-treated motherswere removed and washed. Skin and liver supernatant fractions were prepared and used as the enzyme source. Data represent mean±SD of 3experiments in each of which one mother and a minimum of 8 neonates was used.

b Results statistically different from controls (p<0.05)

Table 4. Effect of cutaneously applied Coal Tar constituents on AHH activity in neonatal rats (Bickers et al., 1982)

Constituenta

AHH (p mole 3-OH BP/min/mg protein)

Skin Liver

Control Treated Control Treated

Benzene 0.51±0.03 0.54±0.04 22.15±4.12 24.81±5.12

Naphthalene 0.53±0.05 0.57±0.07 23.12±3.12 25.89±4.81

Acridine 0.57±0.05 1.23±0.02b 23.17±3.33 27.80±6.67

Anthracene 0.53±0.04 1.43±0.11b 21.16±1.67 58.67±9.67b

Benzo[a]pyrene 0.59±0.04 5.23±0.40b 27.83±8.33 214.50±9.33b

aEach was dissolved in acetone or benzene and administered topically to 4-day old rats in a single dose (100 mg/kg body weight). Animals were killed 24 hourslater. Data represent mean ±SD of 3-4 experiments in each of which a minimum of 6 neonates was studied.

bResults are significantly different from respective controls (p<0.05).

6

Group 3 received a single topical application of Crude Coal

Tar alone (10 ml/kg). Group 4 received UVB followed

immediately by Crude Coal Tar. Group 5 received UVB

followed by acetone. Group 6 received Crude Coal Tar

followed by UVB. AHH, ERD and ECD were determined as

in Das et al. 1986. The quantitation of phenolic BP

metabolites was based on comparison with the fluorescence of

a standard solution of 3-hydroxybenzo[a]pyrene. The effect of

exposure of animals to UVB and Crude Coal Tar, alone and

combined, on cutaneous AHH, ERD, and ECD activities is

given in Table 5. A single topical application of Coal Tar

resulted in significant induction of AHH, ERD, and ECD.

When UVB exposure was added, the result was additive and

synergistic.

Treatment of animals with Crude Coal Tar alone resulted in

352% increased formation of benzo[a]pyrene (BP)

metabolites. Topical application of Crude Coal Tar followed

by exposure to UVB resulted in the highest enhancement of

BP metabolite formation. BP metabolite formation increase

was 834%, 322% , and 373% , respectively, as compared with

the control group, and groups treated with UVB alone, and

with UVB followed by acetone (Mukhtar et al., 1986b).

Pigs

VanRooij et al. (1995) killed healthy domestic pigs (75-100

kg) and retrieved the ears. Five ears were used. Each ear was

cut transversely, distal from the bifurcation of the vena

auricularis lateralis. Cannulas were inserted into the vena

auricularis intermedius and arteria auricularis.

The preparation was perfused with phosphate-buffered saline

until the perfusate was clear. After 30 minutes of perfusion,

industrial Coal Tar was applied on a square area of 6 x 4 cm2

with an average dose of 11 mg/cm2. The range in absorbed

amounts of 10 PAH s through pig ear skin during 200 minutes

after Coal Tar application is given in Table 6 (VanRooij et al.,

1995) .

Hum ans

Bickers and Kappas (1978) studied the induction of AHH by

Coal Tar. Nine patients with psoriasis or atopic dermatitis

applied 100 :l of a 20% Coal Tar solution to clinically

unaffected skin in the lower lumbar region. A second skin

area left untreated or treated with the vehicle only served as a

control. Twenty-four hours later, a 6 mm punch biopsy was

obtained from both sites. The skin samples were

homogenized and AHH activity was measured via a

spectrophotometer. A two- to fivefold increase in AHH

activity was seen in the treated areas compared to the control

sites.

�erníková et al. (1983) selected 28 patients (2 females, 26

males) who required Coal Tar treatment on an area larger than

two-thirds of the body surface. Approximately 1-6 g of Coal

Tar in a paste was spread on the skin in one application.

Urine analysis was carried out before and after the treatment,

and in some cases during the treatment. The presence of

acridine, which is present in Coal T ar, in the urine was

demonstrated by mass spectrographic analysis. The authors

concluded that the presence of acridine demonstrated

absorption of a Coal Tar component through the skin.

Table 5. Effect of UVB and Crude Coal Tar (CCT), Alone and Combined in Neonatal Rats (Mukhtar et al., 1986b)

AHH Activity ERD Activity ECD Activity

Treatment pmol3-OHBP/min/mg

Protein

PercentIncrease over

Control

pmolRF/min/mg

Protein

PercentIncrease over

Control

pmol7-HC/min/mg

Protein

PercentIncrease over

Control

Control 1.75±0.12 1.92 ± 0.14 0.34±0.01

UVB alone 3.97±0.34a 127 4.64±0.27a 142 0.89±0.07a 162

CCT alone 7.85±0.66 350 17.20±2.41b 796 3.47±0.25b 921

UVB+CCT 8.00±0.64b 358 17.89±2.84b 832 3.67±0.27b 979

UVB+acetone 3.27±0.21a 87 3.59±0.31a 87 0.82±0.08a 141

CCT+UVB 16.74±1.06c 858 24.30±2.97c 1166 4.52±0.34c 1229

a Statistically significant from control (p<0.01)b Statistically significant from control and from UVB (p<0.01)c Statistically significant from control, from UVB and from UVB + CCT (p<0.01)

7

Table 6. Absorbed amounts of PAHs through pig ear skin (VanRooij et al., 1995)

PAH Amount Absorbed (pmole/cm2)

Fluorene 222-2377

Phenanthrene 334-1623

Anthracene 47-302

Fluoranthene 23-193

Pyrene 26-193

Benzo[b]fluoranthene <0.1-13

Benzo[k]fluoranthene <0.1-1

Benzo[a]pyrene <0.1-13

Indeno[123-cd]pyrene <0.1-1

Dibenzo[ah]anthracene <0.1-<2

To study the inducibility of AHH, Hukkelhoven et al. (1984)

conducted a study using human volunteers. A circled area of

about 3 cm diameter of the scalp of each volunteer (number

not given) was marked with ink. This area received 5

applications of Coal Tar (0.5 ml) with an interval of 12 hours.

During this period, volunteers did not wash their hair. The

first application was at about 2300 h. In the morning,

volunteers were asked to wash their hair thoroughly to remove

exogenously absorbed Coal Tar. Hair follicles were then

plucked from the study site while control follicles were

plucked from the other side of the scalp. For the measurement

of AHH activity, hair follicles were incubated for 1 hour.

Fluorescence was determined with a Perkin-Elmer 650-40

fluorometer.

Even after extensive washing of the hair after the last Coal Tar

application, some Coal Tar remained associated with the hair.

When the hair follicles plucked from the Coal Tar region were

incubated, a relatively high background fluorescence was

obtained. No fluorescence was extracted from the control hair

follicles. It was also studied whether the effect of Coal Tar on

AHH activity was limited to the treated scalp region. AHH

activity was measured outside the marked area in 3 persons

before and after application of Coal Tar.

The results showed similar enzyme activities before and after

treatment indicating the effect of Coal Tar on AHH activity is

restricted to the trea ted skin surface (Hukkelhoven et al.,

1984).

Storer et al. (1984) gave five volunteers 85 g of a 2%-Crude

Coal Tar in petro latum preparation and instructed them to

apply the medication to the trunk and extremities. The

application was to be done at night and removed 8 hours later

on each of 2 successive days. Blood samples were taken

before the study and after completion of the second 8 hour

application. Blood samples were analyzed by gas

chromatography and mass spectrometry. Values obtained

from the first blood sample were subtracted from those for the

final blood samples. PAHs found in the volunteers’ blood

include naphthalene, biphenyl, acenaphthene, fluorene,

phenanthrene, anthracene, fluoranthene, pyrene, and

benzo[b]thiophene. Absorption of PAHs in Crude Coal Tar

occurred in a variable manner. PAH levels in blood ranged

from undetectable amounts to 100.0 parts per billion.

Van Cantfort et al. (1986) studied BP metabolism by the

incubation of epidermal blisters from 19 volunteers with 0.35

:Ci [14C]BP at 32°C for 24 or 48 hours. The survey found

large variations in basal epidermal activity. Next, 11

volunteers were treated with Coal Tar (one or three

applications at 24 hour intervals) . This resulted in a 2 to 8-fold

increase in BP metabolism. This induction was not increased

with repeated Coal Tar application.

Merk et al. (1987) evaluated the effect of human exposure to

a Crude Coal Tar. AHH activity was measured as well as the

metabolism of BP and benzo[a]pyrene-7,8-diol (BP 7,8-diol).

Twelve healthy volunteers were studied before and after

shampooing their hair daily for 4 days with the Crude Coal

Tar-containing shampoo. Hair follicles were plucked and

incubated in the appropriate solutions for each assay. For the

AHH study, specific basal enzyme activity ranged from 0 .6 to

8.9 fmol/h/hair follicle.

8

Coal tar application caused a 50-148% increase in AHH

activity in 10 of the 12 individuals. The remaining 2

individuals, who manifested the highest basal levels of enzyme

activities, showed a decrease in enzyme activity after use of

the shampoo. For the BP study, 628 fmol of BP derivatives

were detected after a 90 minute incubation. The metabolites

formed were as follows: BP 9,10-diol, 91 fmol; BP 4,5-diol,

64 fmol; BP 7,8-diol, 55 fmol; BP 1,6 -quinone, 171 fmol; BP

3,6-quinone, 174 fmol; 9-hydroxy-BP, 18 fmol; and 3-

hydroxy-BP, 55 fmol. The authors concluded that the BP 7,8-

diol study showed that human hair follicle enzymes are

capable of converting BP 7,8-diol to tetro ls (Merk et al.,

1987).

Jongeneelen et al. (1988) treated five female patients suffering

from eczematous dermatitis on the arms and legs for several

days with an ointment containing 10% Coal Tar. During the

treatment, the ointment was removed daily with arachis oil,

and a fresh dose of approximately 40 g of ointment was

applied for the next 24 hours. The patients collected spot

urine samples, one before the start of the application and two

samples per day (morning and evening) during the first 3 days

of treatment. After the treatment was started, the

concentration of 1-OH-P rapidly increased to about 100-1000

times the background level.

Arnold et al. (1993) investigated the effects of topical

application of isoquinoline (a component of Coal Tar) on

human skin. Of interest was the level of induction of ornithine

decarboxylase (ODC) following tape stripping as an indicator

for potential PK C inhibition in vivo . The subjects included 18

volunteers with no history of skin diseases and 17 psoriasis

patients who had received no therapy for 2 and/or 4 weeks

prior to the study. In each patient, two symmetrical

comparab le lesions designated left and right were selected.

For the volunteers, Crude Coal Tar containing 0.2 %

isoquinoline was applied in an area of 3 cm2 and covered with

gauze. The treated site and a contralateral site were tape

stripped after 16 hours followed by a second application of the

Coal Tar to the treated site. A biopsy was taken from both

sites after 8 hours.

For psoriasis patients, 2 jars, one with Vaseline®

album/lanette wax cream (50%/50%) with 0.2% isoquinoline

and one with basecream only were randomly assigned to the

left or right lesion. Patients were asked to use the creams

twice daily. In their last trial week, the patients applied the

creams on 2 uninvolved areas. On day 21, the different areas

were tape stripped, followed by application of the assigned

cream, and biopsied after 8 hours. Biopsies were

homogenized, and ODC measurements were taken via

scintillation counting. The authors concluded that application

of 0.2% isoquinoline or even Crude Coal Tar did not have any

significant influence on ODC induction (Arnold et al., 1993).

Hansen et al. (1993) studied the urinary excretion patterns of

1-OH-P and "-naphthol in urine in 2 patients. Each subject

was treated once a day with Coal Tar pitch covering >50% of

the skin. After 1 week, the urinary concentration of 1-OH-P

and "-naphthol increased approximately 100 times. However,

after 3 weeks, the urinary concentration decreased to

approximately the pre-experiment levels, even though the

treatment remained unchanged.

VanRooij et al. (1993) applied a dose of 2.5 mg/cm2 Coal Tar

ointment on 24 cm2 skin to the forehead, shoulder, volar

forearm, palmar site of hand, groin, and ankle of 4 male

volunteers. After 45 minutes, the remaining ointment was

removed using tissues with 1 ml TIV-plus cleaner (DEB

Nederland NV), followed by washing with warm water and

soap. The disappearance of the remaining compounds was

monitored up to 55 hours, taking 8-18 measurements per skin

site in triplicate, using a fiberoptic luminoscope, that enables

the measurement of the fluorescence of chemical substances

on and in the upper layers of the skin. HPLC separation of the

Coal Tar combined with fluorescence detection was applied

to estimate the contribution of 11 polycyclic aromatic

hydrocarbons (PAHs) to the luminescence signal as measured

by the luminoscope. The percentage of each PAH is listed in

Table 7.

Table 7. Levels of PAH in Pharmaceutical Coal Tar

(VanRooij et al. 1993).

PAH Level (%) *

Naphthalene 0.13

Fluorene 0.28

Phenanthrene 0.91

Anthracene 0.24

Fluoranthene 1.07

Pyrene 0.81

Benzo[b]fluroanthene 0.60

Benzo[k]fluroanthene 0.31

Benzo[a]pyrene 0.72

Dibenzo[ah]anthracene 0.16

Idenol[123-cd]pyrene 0.38

* Mean value of two measurements

These authors also applied 2.5 mg/cm2 Coal Tar ointment for

three 6 h periods to either the volar forearm, hand (both

palmar and dorsum), neck, trunk, or calf of eight male

volunteers. Sites were covered with plastic and co tton. After

6 hours, TIV-plus cleaner was used in combination with soap

to clean the surface. All urine voided 24 hours before the

application to 3 days after application was sampled.

9

The total 1-OH-P excreted ranged from 5.0 to 23.8 nmol.

There were significant differences in the total excreted amount

of 1-OH-P between individuals, but no significant differences

in the extent of urinary 1-OH-P excretion after Coal Tar

application between the various skin sites. The time in which

half the total 1-OH-P was excreted differed significantly

between the volunteers ranging from 8.2 to 18.9 hours

(VanRooij et al., 1993).

Santella et al. (1994) used Coal Tar treated psoriasis patients

as a model population to test a newly developed ELISA for

the urinary excretion of BP and related PAHs. Urine samples

were collected from 57 patients and 53 untreated volunteers.

Patients applied either an ointment or gel-based Coal Tar

product, or both, to the entire body surface at least once a day,

followed by UVB treatment. Precise dosages were not

possible because treatments were self applied with variable

efficiency. The estimated exposure was 20-100 g of tars/day.

Twenty-four hour urine samples were collected from all

subjects and frozen. 1-Hydroxypyrene (1-OH-P) was

analyzed by HPLC with a fluorometer. PAH metabolites were

analyzed by competitive ELISA.

Urinary PAH metabolites were elevated in patients (mean 730

± 1370 :mol equivalents of BP/mol creatinine) compared

with untreated volunteers (110 ± 90 :mol/mol, P<0.0001).

Urinary levels of 1-OH-P were also elevated in treated

patients (mean 547 ± 928 :mol/mol creatinine) compared with

volunteers (mean 0.14 ± 0.17 :mol/mol, P<0.0001). The

authors indicated there was a good correlation (r=0.717,

n=96, P<0.0001) between the PAH-ELISA data and the 1-

OH-P levels in all subjects (Santella et al. 1994).

van Schooten et al. (1994) assessed the urinary excretion of 1-

OH-P to assess the internal dose of polycyclic aromatic

hydrocarbons after acute dermal application of a Coal Tar

shampoo. A single use of the shampoo resulted in increased

1-OH-P excretion in all 11 volunteers on day 1 compared to

pre-experiment samples. The mean increase was 10 times

pre-experiment values. On day 2, the concentration was still

raised; the mean increase was 5 times pre-experiment values.

Viau and Vysko�il (1995) had one male volunteer suffering

from psoriasis of the scalp and undergoing treatment with a

Coal Tar shampoo provide all his micturitions between two

applications (interval of 4 days). A single treatment with the

Coal Tar shampoo resulted in at least a 10-fold increase in the

excretion of 1-OH-P. The excretion reached its maximum

approximately 12 hours after the treatment and corresponds to

3.45 :mol/mol creatinine.

The use of 1-OHP as a marker for PAH exposure has been

criticized because: 1-Hydroxypyrene levels fluctuate and

decline after initial exposure which prevents constant

monitoring of PAH exposure from coal tar (Hansen, 1993); 1-

Hydroxypyrene is not a suitable marker for low urinary

excretion rates which would result from topical applications

(Jacob, 1989; Grimmer, 1990); and 1-Hydroxypyrene levels

vary dramatically among exposed individuals, especially those

who smoke, even when the exposure rate is constant (Jacob,

1989; Grimmer 1990).

HAIR GROW TH

Ritschel et al. (1975) studied the influence of Coal Tar on hair

growth in New Zealand rabbits. W hite and black rabbits with

two rectangular patches shaved on their backs were used. In

the first experiment, the left side was kept as a control and on

the right side 5% Coal Tar was applied once a day for three

days. On the fourth day, the tar was removed and hairs were

epilated and measured for length. The rate of hair growth for

the white rabbit with Coal Tar was significantly increased but

not for the black rabbit.

For the second experiment the black rabbits were shaved and

killed. A lipid extract and an aqueous extract using a 0.9%

sodium chloride solution were prepared from the skin and

hair, respectively. On the shaved backs of white rabbits 8

areas were marked on each side, the left side the test without

tar, the right side for the test with tar. Two rabb its each were

used for the lipid extracts and the aqueous extracts. The

following areas were used: control, solvent blank, skin extract,

and hair extract. The solvent blanks and extracts were

injected intracutaneously (0.5 ml dose) into the designated

areas. Tar application was done once a day for three days.

The intracutaneous administration of a 0.9% sodium chloride

solution with and without Coal Tar had a stimulatory effect on

hair growth. A slight positive effect occurred when aqueous

skin and hair extracts were used together with Coal Tar.

In the third experiment, the influence of intracutaneous

administration of 0.9% sodium chloride solution and aqueous

extract of skin with and without application of tar on the rate

of hair growth was studied. The extracts were the same as

described for the second experiment. Again, a highly

significant difference occurred with the Coal Tar treatment. A

significant increase was also observed for the intracutaneous

administration of 0.9% sodium chloride solution, which was

further increased when followed by Coal Tar application

(Ritschel et al., 1975).

INFECTION

Stone and W illis (1969) reported the effect of tar on bacterial

infection. The hair was clipped from the backs of 12 adult,

white, male rabbits. Two grams of Coal Tar U.S.P. mixed with

hydrophilic ointment was applied to one side and an equal

amount of base was applied to the opposite side. Sites were

covered with plastic film, covered by gauze, and removed

after 24 hours. A micrococcus suspension (0.2 ml) was

injected into the superficial dermis at both sites. The areas

were again covered by tar and the base. After 24 hours, the

10

sites were uncovered and induration was measured. Yellow

staining and a mild erythema were present on the tar site. The

average diameters of the indurations were 12.7 mm at the tar

sites and 4.3 mm at the control sites.

ANIMAL TOXICOLOGY

SHORT-TERM ORAL TO XICITY

Weyand et al. (1991) conducted palatability experiments using

B6C3F1 mice. Eight groups of 5 male mice were maintained

on a control basal gel diet for 14 days after which seven of the

groups were switched to an adulterated diet containing 0.1,

0.2, 0.5, 1, 2, 5, or 10% Coal Tar. Animals were maintained

on either control or adultera ted diets for another 15 days. A

ninth group of mice received a pellet diet during the 29 day

study. Animals on the control and 0.1, 0 .2, 0.5 , and 1% diets

were killed on day 29.

No difference in body weight was detected between animals

fed a control gel diet or a standard pellet diet. Animals given

2, 5, or 10% Coal Tar adulterated diets refused to eat and

rapidly lost weight. Animals receiving the 0.5 or 1%

adulterated diets initially refused to eat the diets but eventually

tolerated the diets. Animals on the 0 .5% diet regained lost

body weight; however, those on the 1% diet continued their

weight loss. In contrast, animals fed the 0.1 or 0.2%

adulterated diets readily consumed the diet and had weight

gains similar to the controls (Weyand et al., 1991).

Culp and Beland (1994) fed male B6C3F1 mice (8 per dose

group) NIH-31 meal containing 0, 0.10, 0.25 , 0.50, 1.0, or 2.0

g Coal Tar per 100 g meal (or % Coal Tar) for 28 days. A

dose-related decrease in food consumption and body weight

was found. The average body weights and food consumption

over the 28 day period for the 1 and 2% dose groups were

significantly less than the controls (p<0.05). Significant

differences were no t found for the remaining dose groups.

SUBCHR ONIC ORAL TOXICITY

Pinsky and Bose (1988) conducted a study to determine if

chronic exposure to the principal constituents of the aqueous

fraction of Coal Tar extracts could lead to neurological

damage. Forty-two pigmented mice of the Belknap strain

were divided into groups of 6. Six experimental groups

received mixtures of artificial Coal Tar extracts in their

drinking water, a seventh (control) group received tap water.

The solutions were composed as follows: pyridine at 0.2

:l/ml; pyridine at 2.0 :l/ml; a mixture of phenols, cresols, and

xylenols at concentrations approximately equal to those

expected in Coal Tar extracts with the pyrid ine amounts used

above (designated MXT1LO and MXT1HI); and mixtures of

pyridine, phenol, cresols, and xylenol at concentrations

proportional to those found by Perov (1972) in Coal Tar

extracts and again containing pyridine in the above amounts

(designated MXT2LO and MXT2HI). After 3 months of

exposure, the mice were decapitated and their brains and

livers removed and dissected.

There were no significant differences in water consumption

between any of the groups, including the controls. Weight

gain, general health, and behavior were also similar in all

groups. There was no difference in vertical climbing ability

between any of the groups. The MXT2HI mixture produced a

significant increase in lipid peroxidation, relative to that seen

with tap-water, in the striatum, cerebellum, and liver. The 2.0

:l/ml pyridine mixture induced statistically significant

increases in the levels of lipid peroxidation in the striatum and

cerebellum. The striatum was less sensitive to the 2.0 :l/ml

pyridine mixture than to the MXT2HI mixture while the

reverse was true for the cerebellum. The authors concluded

that artificial mixtures of the aqueous fraction of Coal Tar

could exert a distinct regionally selective neurotoxicity in

pigmented mice, with a rank order of regional sensitivity being

striatum > cerebellum > cerebral cortex (Pinsky and Bose,

1988).

SHORT-TERM PARENTERAL TO XICITY

Jorstad (1925) injected 12 male and 10 female rats with 1 cc

of Coal Tar subcutaneously at the same place (location not

given) every seventh day. After the third injection, the rats

had definite signs of malaise. They lost weight, their coats

became yellow and ruffled.

Watson (1935) injected two groups of 12 rats with 0.375 cc of

Coal Tar mixed with 50% rat tissue extract or 50% paraffin

wax over a period of 12 weeks. For the rat tissue extract

group, the numbers of animals alive on the 200, 300, and 400th

day were 7, 7, and 3 respectively. For the paraffin wax group,

the numbers of animals alive on the 200, 300, and 400th day

were 11, 10, and 7, respectively.

Simonds and Curtis (1935) injected 5% Tar residue (in heavy

liquid petrolatum) into 32 healthy rabbits of both sexes,

chiefly rufous reds, into a vein of the ear usually once a week.

Their weights ranged from 2.5 to 5 kg. Depending on the

constitution and local reactions to the first injection, each

animal was given an injection of 0.2 or 0 .4 cc of the Tar-oil

mixture. If an animal became undernourished and appeared

sick, the injections were stopped. One animal received one

injection of 1 cc anthracene intravenously.

All the animals refused to eat for a day or two following the

injections. The majority of the rabbits had signs of respiratory

difficulty and sneezing. All animals died at times ranging from

8 days to over a year after the first injection. A few days

before death, a serosanguineous fluid escaped from the nose

and sometimes the mouth. There was marked weight loss in

all animals that lived less than 9 months (average of 0.8 kg).

11

The decrease was proportionally greatest following the first

injection. Of the 32 rabbits, 15 had no proliferation of either

the bronchial or alveolar epithelium, 4 had very slight

epithelial proliferations, and 13 had marked epithelial

proliferation with metaplasia (Simonds and Curtis, 1935).

Evelo et al. (1989) divided nine one month old male Wistar

rats into three groups. Two groups were injected with 5 or 25

mg/day of a Coal Tar suspension in olive oil for eight days.

After this period, animals were killed and the livers were

isolated. The animals were observed daily. No visible changes

in appearance or behavior were noted; however when the

animals treated with 25 mg/day were handled, contact with the

belly appeared to be painful. The intake of water was

significantly decreased for both treated groups (30.5±6.1 and

22.6±3.1 ml/day for the 5 and 25 mg Coal Tar treated rats

respectively) compared to that of the control animals

(17.5±2 .9 ml/day).

When the livers were isolated, macroscopic observation of the

abdomen revealed the black residue of the injected Coal Tar.

Small fat particles on the liver were similarly blackened. On

the liver of one animal from the 5 mg group, a hollow 7 mm

cyst was present. The mean liver weights were 13.2±0.6,

15.4±2.5, and 16.6±1.7 mg for the control, 5, and 25 mg for

the treated groups respectively. The increased liver weight for

the 25 mg treated groups was statistically significant (p<0.05)

(Evelo et al., 1989).

CHRO NIC ORAL TOX ICITY

Culp et al. (1998) compared the effects in mice of two Coal

Tar mixtures to that of benzo[a]pyrene (BP) after 2 years of

feeding. Mixture 1 was a composite from seven manufactured

gas plant waste sites. Mixture 2 was a composite from two of

the seven waste sites plus a third site having a very high BP

content. Coal Tar diets were prepared by freezing the mixtures

in liquid nitrogen and blending with the appropriate amount of

NIH-31 meal. BP diets were prepared by dissolving the

appropriate amount of BP in acetone and mixing the solution

with the NIH-31 meal. Female B6C3F1 mice were divided

into 14 dose groups of 48 mice each. The dose groups

consisted of 0.01, 0.03, 0.1, 0.3, 0.6, and 1.0% Mixture 1;

0.03, 0.1, and 0.3% Mixture 2; and 5, 25, and 100 ppm BP.

An additional group was fed untreated meal to serve as a

control. All mice, including those that died during the

experiment, were examined. The results of the gross

examinations are given in the Carcinogenicity section.

Mice fed 0.6 or 1 .0% Mixture 1 ate significantly less than the

control mice. Similarly, a significant decrease in food

consumption was seen in mice fed 0.3% Mixture 2. None of

the mice fed 0.6 or 1.0% Mixture 1 survived the treatment

period. Only 21% of the mice in the 0.3% M ixture 1 group

survived the 2-year period, a difference that was significantly

different from the control group (p<0.0001). The survival for

the mice in the 0.0, 0.01, 0.03, and 0 .1% Mixture 1 groups

ranged from 63 to 71%. In mice fed Mixture 2, there was

significantly decreased survival in the 0.3% dose group

compared to the control. All the mice fed 100 ppm BP were

removed from the study due to morbidity or death. A

significant number of mice in the 25 ppm BP group also died

early (Culp et al., 1998).

DERMAL IRRITATION

Sarkany and Gaylarde (1976) applied preparations of Coal Tar

(5-10%) and its components to 2-8 regions on the clipped

backs of albino male guinea pigs. Applications were made

daily for 3 or 4 days. Animals were killed 24 hours after the

final application and biopsies were taken. Increases in

epidermal thickness between 12.4 and 180% were observed.

Foreman et al. (1979) applied 45-55 mg of crude Coal Tar to

the dorsal flanks of hairless hamsters daily for 9 days. In

another study the intervals were 1, 2, 4, and 6 day periods.

After the specified length of treatment, animals were killed

and the skin from the test and control sites were excised. The

measurement of epidermal thickness was performed using a

Quantimet 720 Image Analysing Computer. Epidermal

thickness increased significantly (p<0.05) by Day 2, reaching

an almost two-fold increase by Day 9. Comedo formation was

also noted in many of the sections studied.

REPRODUCTIVE ANDDEVELOPMENTAL TOXICITY

Bacelar (1932) painted 11 female rabbits with tar and

compared them to 2 controls. The absolute and relative

weights of the ovaries were increased among the control

rabbits than among those painted with tar. The author

speculated that painting with tar decreased the number of

interstitial cells in the ovary.

GENOTOXICITY

B AC TER IA L SY STEM S

Coal Tar

Koppers Company, Inc. (no date) examined seven Coal Tar

distillate fractions for mutagenic activity using the Ames

Salm onella/mammalian microsome reverse mutation assay. S.

typhimurium strains TA98 and TA1537 were used with and

without S9. The doses ranged from 0 .00001 to 6.0 mg/plate

and differed for each distillate fraction under study. Also, the

number of experiments performed using each distillate

fraction differed. Only two of the seven Coal Tar distillate

fractions tested were mutagenic to TA98 in the presence of

S9. The other five caused slight increases in the number of

12

TA98 revertants when S9 was present, but these were not

dose-related or reproducible. Likewise, only one Coal Tar

fraction showed an increase in the number of revertants in

TA1537, but the increase was neither dose related nor

reproducible.

Saperstein and W heeler (1979) evaluated four therapeutic

Coal Tar preparations used in the treatment of psoriasis (Zetar

® Emulsion, Estar ®, Lavatar, and Coal Tar Solution USP)

using the Ames Salm onella/microsome mutagenicity test. The

products were screened in strains TA98, TA100, and TA1538

with S9 fraction. Tar preparations were tested at doses ranging

between 10 and 200 :g tar/plate. All of the Coal Tar

preparations were mutagenic within the dose range tested.

Strain TA98 was the most sensitive to the mutagenic effects of

the tar, but a significant increase in his+ revertants was seen

in all three strains.

Fysh et al. (1980) tested the mutagenicity of four commercial

shampoos (Zetar Emulsion®, Tersa Tar ®, Pentrax ®, and

Polytar ®) using S. typhimurium strain TA100 in the presence

and absence of S9. Each sample was extracted with hexane,

and dissolved in dimethylsulfoxide for the mutagenesis assay.

It was decided that 5 :l of each shampoo extract gave close to

optimal results (maximal mutagenicity and minimal toxicity).

If the background rates are subtracted (85-118

revertants/plate), the revertant rates ranged between

approximately 200 and 400/plate.

Santella et al. (1994) analyzed urinary mutagens from healthy

volunteers and from psoriasis patients who applied an

ointment or a gel-based Coal Tar product (or both) to their

entire body surface at least once a day, followed by UVB

treatment. Analysis was carried out on S. typhimurium strain

TA100 in the presence of S9 and $-glucuronidase. Induced

revertants/25 ml of urine for controls ranged from 0 to 480

(mean, 134±99 revertants/25 ml) while in patients the range

was 0-670 (mean, 153±134 revertants/25 ml).

Coal Tar M etabolites

Wheeler et al. (1981) collected urine samples from 12

nonsmoking and 2 smoking psoriasis patients and from 4 non

smoking volunteers (controls). Patients were treated with 1%

Crude Coal Tar U.S.P. or 1 to 10% Crude Coal Tar in

petrolatum in the evening. The following morning, patients

received Coal Tar baths followed by UV light (mainly 290-

320 nm UVB). Urine samples were extracted by adsorption

and assayed in the Ames Salmonella/Microsome test using

strain TA98 with S9. Ten of the 12 nonsmoking psoriatics had

at least one mutagenic urine that was 3 to 10-fold higher than

control urines. Typical values for nonsmoking psoriatics

treated with Crude Coal Tar ranged from 42 to 496 his+/20 ml

of urine after the subtraction of spontaneous his+ counts. Two

nonsmoking normal volunteers were found to excrete

mutagenic urines. The values for smoking psoriatic patients

ranged from 213 to 1100 his+/20 ml urine.

These authors also applied Crude Coal Tar for 3 consecutive

days to 3 male psoriatic patients, followed by exposure to UV

rays for 2 minutes on the first day, 3 minutes on the second,

and 4 minutes on the third. Urine was collected by each

patient starting from 6 hours after the first therapeutic

application of Coal Tar up to 36-48 hours after the last

application. Urinary extracts were tested for mutagenicty in

the Ames plate incorporation assay using S. typhimurium

strains TA98 and TA100 in the presence of S9 both in the

presence and absence of $-glucuronidase. Mutagenicity of the

urinary extracts was detectable at 6-7 hours after the first

application of Coal Tar. In all patients, elevated peak values,

ranging from 37,600 to 129,300 induced revertants/g

creatinine were reached after approximately 50 hours from the

start of the therapy.

Clonfero et al (1986) also tested the Coal Tar preparation in

the Ames plate incorporation assay using the following dose

levels: 500 :g, 100 :g, 10 :g, and 1 :g of Coal Tar in 100 :l

of DM SO per p late in the presence or absence of S9.

Salm onella typhimurium strains TA98 and TA100 were used.

No direct mutagenic activity was found, while after addition

of S9 mix, the Coal Tar was mutagenic on strain TA100 and

TA98 of S. typhimurium. A 2-fold increase over the

spontaneous revertant level was ob tained with the following

doses of Coal Tar/plate: 10 :g/plate on TA98 and 16 :g/plate

on TA100 (Clonfero et al., 1986).

Jongeneelen et al. (1986) conducted the Ames mutagenicity

test using urine from 5 female eczema patients treated with an

ointment containing 10% Coal Tar for several days.

Salm onella typhimurium strain TA98 was used in the presence

of S9 and $-glucuronidase. The mutagenicity of the urine

samples could not be assayed because of the toxic properties

of the urine extract, even after dilution. However, the authors

also used rats receiving topical Coal Tar treatment. The 24

hour urine samples from 3 rats were pooled for the

mutagenicity study using S. typhimurium strain TA98 in the

presence of S9 and $-glucuronidase. There was evidence of a

dose-dependent uptake through the skin. The results are

shown in Table 8.

Clonfero et al. (1987) monitored three male psoriatic patients

during their therapy which consisted of a daily application of

Crude Coal Tar for 3 consecutive days followed by exposure

to UV rays. Urine samples were collected starting from 6

hours after the first Coal Tar application up to 36-48 hours

after the last. Various doses of urine extracts were tested in the

Ames plate incorporation assay using strains TA98 and

TA100 of S. typhimurium in the presence of S9 and $-

glucuronidase. The psoriatic patients had 64,462 induced

revertants/g of creatinine compared to 279 for a group of 5

control subjects. In addition, there was a correlation found

between the total urine PAH levels and mutagenic activity of

13

Table 8. Revertants/plate in an Ames assay of urine of rats treated with Coal Tar (Jongeneelen et al., 1986).

Applied Coal Tar

Time of excretion

0-24 h 25-48 h 48-72 h 72-96 h

0 (mg/rat) 47 49 44 44

2.5 (mg/rat) 90 66 44 44

12.6 (mg/rat) 135 101 74 52

53.0 (mg/rat) 146 141 109 69

the urine extracts of the psoriatic patients.

Clonfero et al. (1989) collected a single sample of urine from

a male psoriatic patient, following a 3 day therapeutical

exposure to pure Coal Tar. The sample was serially diluted

(dilutions ranging from 1:2 to 1:256), using a pool of urine

from subjects not exposed to PAHs. Samples were assayed in

the Ames plate incorporation assay on S. typhimurium strain

TA98 in the presence of S9 and $-glucuronidase. The

mutagenic activity ranged from 563 to 7034 induced

revertants/g creatinine. Clear mutagenic activity was evident

in the dilutions from 1:2 to 1:16.

Sarto et al. (1989) tested the mutagenicity of undiluted Coal

Tar and an ointment containing 4% Coal Tar in the Ames

plate incorporation assay. Dose levels corresponding to 500

:g, 100 :g, 10 :g, and 1 :g/plate (in 100 :l of DMSO) either

of the pure Coal Tar or the ointment were assayed on S.

typhimurium strains TA98 and TA100 in the presence or

absence of S9. The mutagenicity of the 4% Coal Tar ointment,

in the presence of S9, was five times less on S. typhimurium

strain TA100 (0.3 net induced revertants/:g) and 10 times less

on strain TA98 (0.9 net induced revertants/:g) than the

corresponding mutagenicity of the pure Coal Tar. Neither the

pure nor the diluted Coal Tar were mutagenic in the absence

of S9.

In addition, Sarto et al. (1989) collected blood samples from

6 psoriatic patients using either undiluted Coal Tar or the

ointment containing 4% Coal Tar for the evaluation of sister

chromatid exchanges (SCEs). In 5 of 6 patients, chromatid

type breaks and SCEs were significantly increased from

historical averages; however, in comparison to pretreatment

samples, only 2 were significantly increased.

Clonfero et al. (1990) analyzed urine samples from psoriatic

patients treated topically with Coal Tar based ointments using

the Ames plate incorporation test and the fluctuation test.

Assays were done using S. typhimurium strain TA98 in the

presence of S9 and $-glucuronidase. Mutagenicity of the

extracts was detectable down to a dilution corresponding to a

1-OH -P content of about 50 :g/g creatinine and 7 :g/g

creatinine of total PAHs. In the second part of the study, the

minimum mutagenic dose, defined as the minimum

concentration of 1-OH-P which could be hypothesized to

correspond to a positive mutagenic response in each of the

mutagenic assays was calculated. The mean level of 1-OH-P

which could be estimated to correspond to a positive

mutagenic repsonse was 71.5±55.9 :g/g creatinine for the

plate incorporation assay and 33.6±22.5 :g/g creatinine for

the fluctuation test.

MAM MALIAN ASSAYS

Coal Tar

Thein et al. (2000) painted 6-10 week old Muta™Mice

females (CD2-LacZ80/HazfBR) with 10 mg/cm2 of Coal Tar

or corn oil on the dorsal skin, on an area of about 1 x 3 cm.

Concentrations of 25% and 50% Coal Tar were made in corn

oil. The controls were treated with corn oil only. Muta™Mice

were shaved at the lower dorsal area 24 hours prior to

painting. After 32 days, the animals were killed.

The epidermal cells were isolated and DNA was extracted for

in vitro phage packaging. The DNA was added to the

packaging extract and incubated. An overnight culture of E.

coli C lac Z rec A gal E harboring a gal K gal T multicopy

plasmid was innoculated in LB medium, MgSO4, ampicillin,

and kanomycin and grown. The host bacteria were used for

infection after they reached an OD709=1.7-1.9. X-gal is

metabolized by $-galactosidase to yield blue plaques. Phages

were allowed to infect an overnight culture of E. coli C lac Z

rec A gal E . Only phages with an inactivated lac Z gene would

be able to form plaques; bacteria infected with wild type

phages would lyse. Light blue plaques with a partially

inactivated lac Z gene were considered as mutants.

The mutantion frequency in epidermal cells of treated mice

was 2735±281 x10-6 (n=3) and in control mice 171±97 x10-6

(n=5). The authors concluded that that a single painting

induced a 16-fold increase in the number of mutations above

14

the background level (p<0.002) in epidermal cells (Thein et

al., 2000).

Coal Tar M etabolites

Granella and Clonfero (1992) compared the sensitivity of the

pla te incorporation, macro-scale f luctuation, and

microsuspension tests in detecting mutagens in urine of 3 male

psoriatic patients who applied Coal Tar ointments for 4

consecutive days. Urine samples were filtered, eluted, and

dried to obtain a 250 X concentrate for the plate and

fluctuation tests and a 100 X concentrate for the

microsuspension assay. S. typhimurium strain TA98 with S9

and $-glucuronidase was used. A urine extract was considered

positive if it produced at least a doubling of the number of

spontaneous revertants, or in the case of the fluctuation assay,

a O2 statistical significance with p<0.05 .

All samples were mutagenic. Minimum mutagenic doses of

extracts were 1.5-12.5, 0.4–3.1, and 0.5-2.5 ml of urine for the

plate, fluctuation, and microsuspension tests respectively

(Granella and Clonfero, 1992).

Giles et al. (1996) investigated the metabolic activation of

benzo[g]chrysene (B[g]C), a moderately carcinogenic PAH

present in Coal Tar, in mouse skin. B[g]C (0.5 :mol) was

applied to the dorsal skin of male Parkes mice. Control mice

received acetone only. Groups of four animals were killed 6

hours and 1, 2, 4, 7, or 21 days after treatment and the treated

areas of skin were removed and frozen. DNA was isolated for32P-postlabelling. Resolution of 32P-labelled adducts was

performed on TLC sheets and visualized by autoradiography.

Seven principal adduct spots were consistently detected.

Maximum levels of 6.55 fmol adducts/:g of DNA were

detected 24 hours after treatment. There was a loss of 58% of

the damage by day 4, followed by a slower removal of adducts

over subsequent days (Giles et al., 1996).

DNA ADD UCTS

The formation of DNA adducts as a result of Coal Tar

exposure is well recognized --- Table 9 summarizes the

available data.

CARCINOGENICITY

The carcinogenicity of Coal Tar was first reported when a

variety of metastasizing skin cancers occurred in mice painted

with Coal Tar (Yamagiwa and Itchikawa, 1917). The ability

of tar to cause cancer is generally attributed to its PAH

content. According to Lin and Moses (1985), inducible

microsomal enzymes, such as aryl hydrocarbon hydroxylase,

convert these compounds into active forms which then bind to

DNA and RNA, thus exerting their carcinogenic influences of

DNA and RNA.

RAT - SUBCUTANEOUS

Jorstad (1923) injected Coal Tar beneath the epidermis of an

embryonic rat and described how the epithelial cells migrated

towards the drop to form a collar. When injected into

subcutaneous tissue, Coal Tar caused dense masses of

connective tissue cells to develop. These masses became

larger when more tar was added until they were sarcomatous.

MOUSE - ORAL

In the study by Culp et al. (1998) (see Chronic Oral Toxicity

section for details), the tumorigenicity of two Coal Tar

mixtures was compared to benzo[a]pyrene (BP) after 2 years

of feeding in mice. Liver neoplasms occurred in all dose

groups fed Mixtures 1 and 2, but not in the control group. A

s i g n i fi c a n t d o s e - r e la t e d t re n d w a s o b s e rv e d .

Alveolar/bronchiolar adenomas, carcinomas, or both were

present in the control group and in all groups of mice fed

Mixtures 1 and 2. W ith Mixture 1, the incidence in the 0.3,

0.6, and 1.0% dose groups was significantly increased

compared to the control group and a significant dose-related

trend was observed. A significant dose-related trend was also

found with Mixture 2 and the frequency was significantly

increased in the 0.1 and 0.3% dose groups. The predominant

lung lesions were adenomas, with only 15 carcinomas

detected. Papillomas and/or carcinomas of the forestomach

squamous epithelium were observed in all groups of mice

treated with Mixtures 1 and 2 but no neoplasms were detected

in the control group.

MOUSE - DERMAL

Murphy and Sturm (1925) studied the influence of external

application of Coal Tar on the incidence of lung tumors in

mice. The tar product used had for its base the residue from

a coke oven in which the crude tar had been distilled at a

temperature of approximately 377°C. The mice came from a

stock with an extremely low cancer incidence. For each

experiment, each mouse received Coal Tar on 12 areas, each

less than a centimeter in diameter, painted in rotation such that

36 applications were distributed over 83 days. Each site was

painted three times with a month in between. In the first

experiment, 20 mice were painted according to the above

scheme. As a control, 22 mice from the same stock were kept

under the same laboratory conditions.

The lung tumor rate for the treated group in this experiment

was 66.6%. N one of the control animals showed developed

tumors. In the second experiment, an unspecified number of

mice were subjected to the same system of applications as that

in the first experiment. The lung tumor rate was 60%;

however, 1 mouse had a tumor of the uterus. In the third

experiment, 40 mice were painted in the same fashion as in the

15

Table 9. Studies on Coal Tar and DNA adducts

Reference Test system Results

Mukhtar et al. 1986c male SENCAR mice Topical application of 0.5 ml of Crude Coal Tar resulted in the formation of 278 fmol and410 fmol BPDE-I-dGa adducts per mg DNA in the epidermis and lung, respectively.

Schoket et al. 1988a male Parkes mice The application of 150 :l of 20% pharmaceutical grade Coal Tar solution resulted in ~0.4fmol total adducts/:g DNA 24 hours after treatment. When given multiple treatments, asteady accumulation of adducts was seen in skin DNA.

Schoket et al. 1988b Adult and fetal humanskin samples

A single dose of pharmaceutical grade Coal Tar (equivalent to 30 mg Crude Coal Tar)resulted in 0.2 to >0.6 fmol adduts/:g DNA.

Schoket et al. 1990 male Parkes mice skin Application of 45 mg of Coal Tar ointment resulted in 0.5 fmol/:g DNA in the skin 1 dayafter the five treatments.

Human skin biopsysamples

Biopsies taken 24 hours after 5 treatments with Coal Tar ointment contained adductsranging from 0.1 to 0.39 fmol/:g DNA.

Zhang et al. 1990 Human skin biopsysamples

Topical application of 10-50 mg/kg/day of Coal Tar for at least 7 days produced adductlevels ranging from 0.18 to 9.4 adducts/108 nucleotides.

Weyand et al. 1991 B6C3F1 mice A dose related increase in DNA adduct levels was observed in the lung tissue of mice fed0.1, 0.2, 0.5, and 1% Coal Tar diets. Adduct levels were 4 times greater in mice fed a 0.5or 1% diet relative to those fed a 0.1 or 0.2% diet.

Paleologo et al. 1992 Human lymphocytes Psoriatic patients treated with Coal Tar products had mean adduct levels of 0.257±0.162fmol BPDE/:g DNA in their white blood cells during treatment.

Pavanello and Levis 1992 Human lymphocytes No significant differences were found in the amounts of total DNA adducts betweenpsoriatic patients treated with Coal Tar and controls or between psoriatic pateints beforeand after Coal Tar treatment.

Hughes et al. 1993 Male Parkes mice When a group of PAHsb were applied to mouse skin, the pattern of adducts formed in theskin resembled that elicited by the application of Coal Tar solution

Pfau et al. 1993 Male Parkes mice A major DNA adduct formed in the skin of mice treated with pharmaceutical grade coaltar was found to be derived from benzo[a]pyrene rather than benzo[b]fluoranthene

Pavanello and Levis 1994 Human lymphocytes In psoriatic patients treated with crude Coal Tar, there was no correlation between thelevels of PAH-DNA adducts and the exposure to Coal Tar. According to the authors, CoalTar treatment should not be considered a potential genetic and carcinogenic risk forpsoriatic patients.

Culp and Beland 1994 Male B6C3F1 mice Adduct levels were greater in Coal Tar fed mice compared to those fed benzo[a]pyrene. InCoal Tar fed mice, adduct levels were in the order of lung>liver<forestomach.

Santella et al. 1995 Human lymphocytes PAH-DNA adducts were elevated in Coal Tar treated psoriasis patients compared tocontrols (6.77±12.05 adducts.108 nucleotides).

Giles et al. 1997 Male Parkes mice When 0.5 :mol of benzo[c]chrysene, a component of Coal Tar was applied to the skin ofmice, a maximum adduct level of 0.89 fmol adducts/:g of DNA was detected in the skin.

Godschalk et al. 1998 Human skin When eczema patients were topically treated with Coal Tar, median aromatic DNA adductlevels significantly increased in the skin from 2.9 to 63.3 adducts/108 nucleotides.

Human lymphocytes Median aromatic DNA adduct levels were significantly increased in lymphocytes from0.33 to 0.89 adducts/108 nucleotides.

Pavanello et al. 1999 Human lymphocytes Psoriatic patients treated with Coal Tar had 0% of their BPDE-DNA adduct levelsexceeding the 95 percentile control subject value.

Koganti et al. 2000 Female CD-1 mice In animal feeding studies, 7H-benzo[c]fluorene, a PAH in Coal Tar, is a potent lungadductor.

a BPDE-I-dG = benzo[a]pyrene diol epoxide-I-deoxyguanosineb Concentrations of benzo[a]pyrene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, dibenz[a,h]-anthracene,indenol[1,2,3-cd]pyrene, benz[a]anthracene, and cyclopental[cd]pyrene equivalent to those present in 30 mg of Coal Tar were used

16

first experiment. For controls, a group of 16 untreated mice

from the same stock were kept under the same conditions.

While none of the control mice had any tumors, the tumor

incidence for the painted animals was 78.3% (Murphy and

Sturm, 1925).

Watson and Mellanby (1930) studied the effects of

pretreatment of the skin and diet on Coal Tar induced

carcinogenesis, but much experimental detail is lacking in the

report.

Pretreatment with tannic acid (saturated aqueous solution) or

by application of homologous fat (ether extracted from mouse

carcases) followed by Coal Tar application was done for 120

days in 70 animals for each group. The animals were

followed for one year. The authors concluded that the rate of

growth of tumors was unaffected by tannic acid pretreatment,

but accelerated by fat pretreatment, compared to controls.

Pretreatment with olive oil was done in another group of 70

animals for 90 days. According to the authors, animals in the

olive oil + Coal Tar group showed a greater tendency to

develop tumors than the control group. This is a different

measure than above, where rate of growth was determined.

Pretreatment with ether (to remove fatty substances in the

skin) prior to Coal Tar treatment was done in another group of

60 mice for 120 days. Animals were followed for 360 days.

The authors interpreted the results to suggest that the rate of

tumor growth was inhibited by ether pretreatment. Lung

nodules in tumor-bearing animals were reduced in the ether

pretreatment group, as well.

In another experiment, a diet rich in butter was compared to

control diet. Animals (70 in each group) were treated with

Coal Tar daily for 120 days and followed for 360 days. More

animals in the butter diet group had tumors than the controls,

and those in the butter diet had a higher proportion with lung

nodules than the control group (Watson and Mellanby, 1930).

Seelig and Cooper (1933) tested the effect of light on cancer

in mice. Three sets of mice were used in this experiment: (1)

125 male mice for tarring in the dark; (2) a similar group of

125 mice for tarring in the light; and (3) a similar group of 50

which were kept as untarred controls in the dark. Coal Tar

(distillate at 370°-440°C was collected) was applied to the

interscapular region at the root of the neck, over an area about

1.5 cm in diameter. The time intervals between applications

were varied to meet the problem of high death rates in the

mice. Applications continued until the death of the last tarred

mouse. A necropsy was performed on all mice that died. Only

growths that infiltrated the subcutaneous muscle layers were

considered carcinomas. The last mouse in Group 1 died 23

weeks after the first application and the number of carcinomas

in the group was 11. In contrast, the last mouse in Group 2

died 32 weeks into the experiment and there were only 5 cases

of carcinomas in the group. When the last tarred mouse died,

only 58% of the control mice had died and none of the Group

3 mice had carcinomas. The authors concluded that the

absence of light did not compromise the health of mice and

that white light was not a necessary factor in the development

of tar cancer in mice.

Berenblum (1948) painted 12 white mice twice weekly for 41

weeks with undiluted Coal Tar on a small area of the skin in

the interscapular region. Papillomas appeared in the treated

areas in seven of the mice. Of these seven, four subsequently

developed malignant growths, which were found to be

squamous cell carcinomas. There were no metastases.

Christie and McCallum (1958) studied the carcinogenicity of

brown Coal Tar. Included in their experiments were two

treatments (8 mice each, C3H strain) where (1) brown Coal

Tar ointment, identical with black Coal Tar ointment APF, but

substituting brown Coal Tar for black and (2) black Coal Tar

ointment were applied on the back and flank of the mice once

per day, six days per week. In the brown Coal Tar ointment

group, no papillomata, warts or deranged keratinisation

occurred in 8 months of painting. In the black Coal Tar

ointment group, five animals developed warty papillary

growths from 6-8 months, but no malignant tumors were

obtained.

Wright et al. (1985) performed painting assays on Charles

River CD-1 mice (numbers not given). Industrial Coal Tar

from the National Bureau of Standards (NBS) and the Coal

Tar portion of a pharmaceutical stock material were diluted

1:1 by weight in methylene chloride and applied to the shaved

backs of the mice in 50 :l volumes. Two weeks after

initiation, 50 :l of phorbol myristate acetate were applied to

the treated area twice weekly for 6 months. Both the NBS

Coal Tar and the Coal Tar isolate from the pharmaceutical

stock produced tumors in all the mice after 169 days.

Mukhtar et al. (1986a) applied a single dose of 200 :l of

crude Coal Tar in 0.2 ml of acetone to 20 female SENCAR

mice. The mice were shaved and depilated before the

experiment. Skin tumor formation was recorded weekly and

tumors greater than 1 mm in diameter were included in the

cumulative total only if they persisted for 2 weeks or more.

The first appearance of tumors occurred at 6 weeks. After 8

weeks, there were 46 cumulative tumors in the group of mice.

At the termination of the experiment after 11 weeks, 100% of

the mice had tumors and the average number of tumors/mouse

was 3.3.

Warshawsky et al. (1993) painted Coal Tar (in toluene such

that it contained 0.0006% benzo[a]pyrene) on the clipped

backs of male C3H/HEJ mice twice weekly for up to 66

weeks. Observations of the skin were recorded. Lesions

persisting for at least one week which were a minimum of 1

mm3 in size were considered papillomas. The times and

17

appearance of tumors and time for their progression to

malignancy were noted. A necropsy was conducted on all

animals. Tumors were present in 51% of the mice. The latent

period was 73 weeks.

Phillips and Alldrick (1994) attempted to determine whether

treatment with Coal Tar followed by dithranol was

tumorigenic. Female CD-1 mice were treated topically 5 times

a week with 1.5% Coal Tar ointment (50 mg per treatment) for

2 weeks and then with 0.1% dithranol cream (50 mg per

treatment) three times weekly for 40 weeks. Other groups

received either Coal Tar or dithranol alone. Hair on the mice

was shaved and the material was applied to the whole of the

shaved area. Tumors >1 mm were scored. The animals were

killed by cervical dislocation and subjected to post-mortem

examination. None of the mice treated with Coal Tar or

dithranol alone developed tumors during the experiment.

However, four mice that had received Coal Tar followed by

dithranol developed papillomas and 12 mice had enlarged

cervical lymph nodes. Five mice that received d ithranol only

also had enlarged lymph nodes, though this condition was not

seen in any of the mice treated with Coal Tar only.

MOUSE - MUCOSAL

Shabad (1927) applied Coal Tar to the rectum of 78 juvenile

white mice 2-3 times a week. A thin smooth round wooden

stick with a blunt tip was dipped in Coal Tar and carefully

inserted 1.5-2 cm into the rectum. Of the 37 animals that

survived the first 6 months of the test, cancer of the perianal

skin developed in 21 (56.7%).

RABBIT - DERMAL

Itchikawa and Baum (1925) conducted three experiments

using rabbits (strain unspecified). In the first experiment 6

rabbits had Coal Tar painted on their ears in addition to being

fed 10 grams of anhydrous lanolin mixed in the food. In the

second experiment, 6 rabbits had Coal Tar painted on their

ears in addition to being fed 0.5 cc of a 2% watery solution of

potassium arsenite mixed in the food. In the third experiment,

6 rabbits had Coal Tar painted on their ears. The painting

covered the entire inner surface of rabbits’ ears and was

performed usually twice a week for 10 weeks. After the

painted area dried, the coal tar was easily removed with

tweezers, and the ears were repainted. The appearance of

folliculo-epithelioma and its transformation into the early

stage of carcinoma appeared around the same time in all the

animals, but the alteration of the early stage into advanced

carcinoma took place sooner in the animals that were fed on

arsenic and lanolin than in those that were painted with Coal

Tar alone.

Kligman and K ligman (1994) applied ~10 mg of crude Coal

Tar on albino rabbit ears at 0.001, 0.01, 0.1 and 1.0% with 5

weekday applications for 3 weeks and at 10, 25, and 100%

three times weekly for up to 15 weeks. Crude Coal Tar,

whether applied at 10, 25, or 100% was carcinogenic. W ith

10% Coal Tar, tumors developed as early as 1-2 weeks

following 3 weeks of treatment. With longer term treatment,

the number of tumors increased. No results were reported for

Coal Tar concentrations at 1.0% or less.

These authors also applied ~10 mg of crude Coal Tar on

albino rabbit ears at 0.001, 0.01, 0.1 and 1.0% with 5 weekday

applications for 3 weeks and at 10, 25, and 100% three times

weekly for up to 15 weeks. The vehicle was petrolatum.

Crude Coal Tar, whether applied at 10, 25, or 100% was

comedogenic. The threshold for comedogenicity was less than

0.1% with 3 weeks application (Kligman and Kligman, 1994).

CLINICAL ASSESSMENT OF SAFETY

DERMAL IRRITATION

Burden et al. (1994) patch tested 74 psoriasis patients with

Coal Tar 3% pet. A positive reaction was followed by dilution

series testing down to a concentration of 0.1%. Of the 74

patients, 13 reported that they were allergic to coal tar;

however, in actuality only 2 had a positive patch test reaction

confirmed by serial dilutions.

PHOTO SENSITIZATION AND PHO TOTOXICITY

Several of the polycyclic aromatic hydrocarbons which make

up coal tar are photosensitizers and cause phototoxicity by an

oxygen dependent mechanism (Gould et al. 1995). Ultraviolet-

A (UVA) light contains the part of the light spectrum that

activates coal tar (Arno ld 199 7). Studies on

photosensitization and phototoxicity of Coal Tar are

summarized in Table 11.

FOLLIC ULITIS

Folliculitis is associated with the prolonged use of some tars

(Lerner and Lerner, 1960).

COM EDOGENICITY

Kaidbey and Kligman (1974) applied 25% crude Coal Tar to

the backs of adult males for 3 times a week for 3 weeks.

Biopsy specimens were obtained at 7, 14, and 21 days and

sporadically thereafter. Caucasians and African Americans

differed in their responses. In Caucasians, the response was

primarily inflammatory. In African Americans, the

inflammatory phase was largely absent. Instead, small open

comedones began to appear after 14 days and were obvious by

the end of the treatment period.

18

Table 11. Studies on Coal Tar photosensitization and phototoxicity.

Reference Summary

Starke and Jillson 1961 Case Report - A 37 year old male had eczema and weeping to patch tests of Coal Tar. A photopatchdeveloped an even more eczematous reaction.

Everett et al. 1961 When Coal Tar solution and ultraviolet light were applied to the skin of 21 persons, erythema andtanning were more prominent at the control sites in all patients

Everett and Miller 1961 When Coal Tar solution (USP) and ultraviolet light were applied to the skin of five adult males,erythema was greater in the tar-free areas than the tar-exposed areas

Kaidbey and Kligman 1974b The intensity of the phototoxic response to Coal Tar was strongly influenced by the vehicle, withvanishing cream producing the greatest reaction (erythema and minimal edema)

Kaidbey and Kligman 1975 When 40 :l of a 25% Coal Tar distillate was applied to the skin of adult males irradiated with UVAalone, the epidermis was largely unaffected except for occasional intercellular edema.

Kaidbey and Kligman 1977 Volunteers who applied a 5% concentration of four different crude Coal Tars followed by UVAexposure experienced whealing followed by raised lesions.

Kroon 1983 40 out of 194 patients photopatch tested with Waxtar (Coal Tar 5%) had phototoxic reactions. 4 patientsdeveloped pigmentation 7 days after irradiation.

Diette et al. 1983, 1985 The time between tar removal and UVA irradiation was important in determining the minimalphototoxic dosea and the minimal smarting doseb in human volunteers.

Berne and Fischer 1987 Compared to Balnetar® and Spiritus carbonis detergens, 5% crude Coal Tar gave the strongest erythemaphototoxicity. Its action spectra ranged from 330 to 400 nm.

a Minimal phototoxic dose: the minimal UVA dose required to induced delayed erythema b Minimal smarting dose: the minimal UVA dose required to induce an immediate smarting reaction

Mills et al. (1978) applied 15% crude Coal Tar in Hydrophilic

Ointment USP to the upper backs of 5 adult males. The agent

was applied to 8 cm squares of skin thrice weekly. Before

renewing the applications, one-half of each square was

subjected to UVA radiation. A combination of open and

closed comedones was present in each of the 5 subjects

receiving Coal Tar without radiation. Comedones and papules

increased in size and number when irradiated.

CASE REPORTS

Table 12 summarizes case reports involving Coal Tar.

CLINICAL TESTING

Wright et al. (1992) divided 15 healthy volunteers (11 women,

4 men) into 3 groups of 5, subjecting them to different modes

of application of Berniter®, a 0.5% coal tar preparation for

the scalp. In application mode 1, Berniter® was applied twice

a week over a period of 8 weeks; in mode 2, it was applied on

a daily basis for 8 weeks. The preparation was administered

by wetting the scalp with water, spreading and massaging the

preparation into the scalp, rinsing the hair and scalp with

water, spreading and massaging the preparation into the scalp

again, and allowing the preparation to work for 5 minutes. In

application mode 3, Berniter® was applied every other day

over a period of 4 weeks. Here the preparation was applied

under occlusion (a plastic cap) and allowed to work for 15

minutes. The test subjects’ 24-hour urines were tested for

low-molecular phenol bodies before and after treatment. In

addition, multiple chemical analyses were undertaken (GOT,

GPT, Gamma-GT , AP, LDH, cholinesterase, total bilirubin,

etc.) as well as creatinine clarance, gel-electrophoresis protein

excretion pattern, and alanine aminopeptidase activity.

No pathological findings were noted in any of the test

subjects. The results of the blood and urine studies, as well as

of the multiple chemical analyses, were all within normal

limits (Wright et al., 1992)

CLINICAL TESTING FOLLOW-UP

Kaaber (1976) reported on 326 patients treated with Coal Tar

for atopic dermatitis. Patients were followed for 42 years to

determine if they had developed cancer. These 326 patients

had been treated in the Department of Dermatology, Finsen

Institute, Copenhagen, Denmark from 1930 to 1939 for atopic

dermatitis. The follow up period for each patient was

calculated from the first examination until the date of death or

19

Table 12. Coal Tar case reports.

Reference Summary

Hodgson, 1948 A 62 year old male using Coal Tar to treat pruritus developed epithelioma.

Simon and Brandt, 1953 A 60 year old female with a history of psoriasis had a positive reaction to a patch test with 2% crude Coal Tarin an oxycholesterol-petroleum ointment base.

A 64 year old female had a positive reaction to a patch test with 3% crude Coal Tar in petrolatum witherythema and edema occurring within 48 hours.

Alexander and Macrosson, 1954 A 31 year old male using a 20% Coal Tar in emulsifying base ointment to treat psoriasis developed squamousepithelioma.

Person and Rogers III, 1976 A 53 year old male using the Goeckerman regimen to treat psoriasis developed bullous pemphigoid.

A 53 year old male using 2% crude Coal Tar to treat psoriasis developed bullae.

A 66 year old male using the Goeckerman regimen to treat psoriasis developed a bulla.

Durkin et al., 1978 A 32 year old male psoriatic developed melanoma after 16 years of treatment with UV light and Coal Tar.

Koerber et al., 1978 A 53 year old female using Coal Tar creams to treat psoriasis developed bullous pemphigoid.

Gonçalo et al., 1984 A 25 year old female with psoriasis had a positive reaction to a patch test with Coal Tar.

A 17 year old female with psoriasis had a positive reaction to a patch test with Coal Tar.

Kokkini and Giotaki, 1984 A 45 year old female psoriatic developed pancytopenia due to hypoplastic and ineffective bone marrowfollowing 5% Coal Tar cream application for 6 months.

Riboldi et al., 1986 A 54 year old female with psoriasis had a positive reaction to a patch test with Coal Tar (blistering).

Illchyshyn et al., 1987 A 31 year old female with eczema had a positive reaction to patch tests with 1% and 5% Coal Tar inpetrolatum.

McGarry and Robertson, 1989 A 67 year old male with scrotal psoriasis developed squamous cell carcinoma after uing a 10% crude Coal Tarointment.

Cusano et al., 1992 A 57 year old male had a positive reaction to a patch test with Coal Tar (5% pet).

Landro et al., 1992 A 29 year old male with psoriasis had a positive reaction to a patch test with 0.05% Coal Tar.

Ibbotson et al., 1995 A 29 year old female asthmatic had severe symptomatic bronchoconstriction which was likely due to inhalationof Coal Tar vapor from the application of Coal Tar bandages. An inhalation challenge test with vapor from theCoal Tar bandages produced a 28% reduction in forced expiratory volume.

Clark and Sheretz, 1998 A psoriasis patient had positive allergic reactions to Coal Tar diluted to 1% and 5% when given patch tests.

until cancer was diagnosed. The expected cancer rated was

calculated based on the cancer registry data on the incidence

of cancer in Denmark. The values were then compared to the

results of the follow up of the 326 patients. There was no

sufficient deviation in the expected values versus the observed

values for the 326 patients treated for atopy.

Maughan et al. (1980) performed a 25 year follow-up study on

305 patients with atopic dermatits or neurodermatits who

received Coal Tar and UV treatment (Goeckerman therapy)

from 1950 through 1954. These patients were located and

contacted by either a follow-up questionnaire or telephone in

order to determine if any malignancy of the skin or other

cancer had developed since the initial treatment. The numbers

of persons in whom skin cancers were expected to develop

were calculated using data from the Third National Cancer

Survey. Of the 305 patients, 13 reported skin cancer had

developed after the initial Goeckerman therapy. Eight patients

had basal cell carcinomas, one had a squamous cell

carcinoma, two had an unknown skin malignancy, and two had

malignant melanomas. The maximum number of people in the

study who would have been expected to have developed non-

melanoma skin cancers if they had lived in any of the regions

reported in the Third National Cancer Survey was 18.8 for the

20

Dallas-Fort Worth area. Since 11 patients developed non-

melanoma skin cancer, no significant increase in the incidence

of skin cancer was seen in the population of patients when

compared to the expected occurrence of skin cancer if the

population were to have resided in the D allas-Fort Worth area.

In a later study, Pittlekow et al. (1981) performed another 25

year follow-up analysis of patients receiving Coal Tar and UV

treatment from 1950-1954. Patients were instructed to report

any cancerous lesions of the skin that had been removed since

the initial Goeckerman treatment. Of 260 patients, 20 (7.7%)

had one or more reported carcinomas of the skin. One patient

reported the development of a malignant melanoma; the

remaining 19 reported either basal cell or squamous cell

carcinomas or unknown varieties of cutaneous malignant

neoplasms. Comparing the group of patients in which skin

cancer subsequently developed with the group in which it did

not, there was no appreciable difference in the median number

of days of Coal Tar treatment.

The Pittlekow study also contains the results from a review by

the National Psoriasis Foundation on the medical histories of

15,000 of its members. The results from that review found no

suggestion of an increased risk to skin cancer. The results of

this survey also showed no increase in skin cancer from

patients who had been treated with Coal Tar.

Larko (1982) conducted a study in Sweden on 85 psoriasis

patients extensively treated with UVB light and topical Coal

Tar. The results were compared to 385 individuals in a control

group. The incidence of premalignant/malignant skin lesions

was only 5.96% in the 85 treated psoriasis patients, but was

10.1% in the 385 control individuals. The authors conclude

that it is unlikely that treated psoriatic patients will have an

increased incidence of malignant skin lesions from their

treatment with topically applied Coal Tar and UVB light.

Jones et al. (1985) compared the observed incidence of

carcinoma in 719 psoriatics treated with Tar with that

expected in the general population. The 719 patients (305

males and 414 females) had received topical Tar therapy

intermittently over a 10 year period between 1953 and 1973.

There were 19 cases of cancer in the male patients which was

very similar to that expected from the general population. In

the case of female patients, the 12 cases found was less than

expected. Of particular interest were the rates of cancer in the

skin and b ladder, neither of which showed a significant

increase in the patient population. The authors concluded that

long-term Tar therapy was not associated with an increase in

cutaneous or non-cutaneous malignancy in patients with

psoriasis.

Bhate (1993) published the results of an epidemiology study

on the use of Coal Tar in the treatment of psoriasis. Between

1977 and 1983, 2,247 patients were treated with Coal Tar at

the Department of Dermatology, Royal Victoria Infirmary,

UK where they were examined for the prevalence of both skin

and internal malignancies. These results were compared

against 4,494 matched control individuals. The results of this

extensive epidemiological study were that there was no

difference in the age of onset of skin cancers between

psoriatics and controls. There was also no evidence of a

cumulative therapeutic risk. Finally, there was no difference

in the prevalence of non-skin cancers between psoriatics and

controls.

Jemec (1994) published results from 88 patients treated

extensively with Coal Tar in Denmark from 1917 to 1937.

Cancers were identified through the Danish Cancer Registry

and relative risk of cancer was calculated. No overall risk of

cancer for the treated patients was found in the 88 patients

compared to the incidence of cancer in the general population.

The authors go on to state that these data provide further

support for the safety of Coal Tar in the management of

dermatological disease.

EPIDEMIOLOGY

Franssen et al. (1999) performed a retrospective study on the

reproductive toxicity of Coal Tar in humans. Women were

chosen based on past history of psoriasis or dermatitis. Out of

103 pregnancies there were 59 in which no Coal Tar had been

used, 21 in which it was uncertain whether or not Coal Tar

had been used, and 23 in which Coal Tar was definitely used.

Of the 59 in which no Coal Tar had been used, 19% of the

pregnancies ended in spontaneous abortion and 5% in a

congenital disorder. In the 23 cases in which Coal Tar was

used during pregnancy, 26% resulted in spontaneous abortion

and 4% in a congenital disorder. T he authors note the small

sample size of patients exposed to Coal Tar and the lack of

uniformity regarding the time and duration of exposure.

In a study completed in Yugoslavia, Vlajinac et al. (2000)

found that the use of tar for cosmetic purposes was a risk

factor for basal cell carcinoma. Participants (200 confirmed

cases of basal cell carcinoma and 399 control subjects) were

interviewed by physicians and given questionnaires regarding

various risk factors. The use of tar was found to be a

significant risk factor (p=0.0064). However, the authors also

used oral methotrexate and photochemotherapy (PUVA) and

the effects from Coal Tar cannot be separated out as the sole

cause.

RISK ASSESSMENTS

The International Agency for Research on Cancer (IARC)

reviewed PAHs as well as Coal Tars in 1984 (IARC 1985).

IARC concluded: “There is sufficient evidence for the

carcinogenicity in experimental animals of coal-tars,

creosotes, creosote oils, anthracene oils and coal-tar pitches.”

IARC evaluated the limited epidemiological studies generated

21

on the therapeutic use of Coal Tar up to that point in time, but

could not draw any conclusions. The therapies were mixed in

most studies and therefore effects from Coal Tar alone could

not be evaluated.

In a review of the use of dermatologic drugs during

pregnancy, Bologa et al. (1992) suggested limiting the use of

Coal Tar to the second and third trimesters, once

organogenesis is complete. In a review of the use of OTC

drugs during pregnancy, Conover and Rayburn (1992),

however, believe the risk of congenital anomalies in children

of women treated with Coal Tar during pregnancy is unlikely.

Pion (1995) examined the question of whether the use of Coal

Tar in dermatological practice was a cause of concern. From

his extensive review of both animal and human data, he stated

that “conclusive evidence for the carcinogenicity of coal tar

used in dermatologic practice is lacking.”

Hess (1999) used BP data as a surrogate to perform a

quantitative risk assessment on Coal Tar as an ingredient.

Rinse-off hair care products contain 1% refined Coal Tar that

were stated to include a maximum level of 50 mg/kg BP.

After a typical application of 12 g, it was estimated that 1% of

the product remains after rinsing. The lifelong exposure to BP

was estimated to be not higher than 0.001 ng/cm2 of exposed

skin surface area per day, which was below the BP no-effect

level. The author concluded that the safety of cosmetic usage

of coal tar was further confirmed by extensive

epidemiological data showing that no carcinogenic

consequences have emerged from its well-established and

intense use in dermatological therapy.

Fehling (2000) stated that an absorbed dose of 52.12 mg/day

was the no significant risk level (NSRL) for Coal Tar

containing products.

Jackson (2003) generated a quantitative risk assessment for 8

Coal Tar containing products, one soap bar, two ointments,

and 5 shampoos by chemically analyzing the PAH content of

these products. The life time averaged absorbed dose for each

of these Coal Tar containing products was significantly below

the 0.0600 :g/day NSRL for benzo[a]pyrene, a known

genotoxic chemical.

Coal Tar itself is on California’s Propo sition 65 list of

substances known to be carcinogenic; soots, tars, and mineral

oils (untreated and mildly treated oils and used engine oils)

are also listed (OEHHA 2003).

SUMMARY

Coal Tar is a semisolid byproduct obtained in the destructive

distillation of bituminous coal, produced in coking ovens as a

byproduct in the manufacture of coke. Coal Tar is a nearly

black, viscous liquid, heavier than water, with a naphthalene-

like odor and a sharp burning taste. Crude Coal Tar is

composed of 48% hydrocarbons, 42% carbon, and 10% water.

Coal Tar is an active ingredient in OTC drug products and is

described as an antidandruff agents, cosmetic biocides, and

denaturant in cosmetics. Coal Tar is monographed by the

Food and Drug Administration (FDA 1991) as a Category I

(safe and effective) for OT C drug ingredient for use in the

treatment of dandruff, seborrhoea, and psoriasis. While Coal

Tar was reported in 2002 to FDA to be used in four

formulations, these uses are OTC. No uses of Coal Tar as a

cosmetic biocide or denaturant have been reported. The

concentration of use of Coal Tar was reported as fo llows:

Shampoos (OTC) (1-7%), Bath soaps and detergents (OTC)

(0.06-5%), and Lotions (OTC)(5% ).

Mice, rats, and humans given a single dose of Coal Tar

solution orally resulted in the induction of one or more of aryl

hydrocarbon hydroxylase (AHH), ethoxyresorufin deethylase

(ERD), and 7-ethoxycoumarin O-deethylase (ECD) activities

in the skin and liver (liver studies not performed on humans).

The absorption of Coal Tar through skin and its systemic

distribution is confirmed by these AHH, ERD, and ECD

induction studies. The absorption of specific Coal Tar

polycyclic aromatic hydrocarbons (PAH s) was demonstrated

in a pig ear skin penetration study. The presence of acridine,

and other Coal Tar PAHs, in urine of patients or healthy

volunteers treated with Coal Tar demonstrated absorption of

Coal Tar.

In short term animal studies mice fed Coal Tar at

concentrations over 2% in their diet found their diet

unpalatable, but no adverse effects were reported other than

weight loss.

Injection of 1 ml Coal Tar 3x over 21 days produced malaise

in rats. Injection of a 5% Tar residue in rabbits produced

eating avoidance, respiratory difficulty, sneezing, and weight

loss. Injection of 5 mg/kg day-1 of a Coal Tar suspension for

8 days in rats decreased water intake, resulted in black

residues in the liver, and increased liver weights.

In a subchronic neurotoxicity study using mice using 2.0 :l/ml

of a mixture of phenols, cresols, and xylenols at

concentrations approximately equal to those expected in Coal

Tar extracts, regionally selective toxicity was found, with a

rank order of striatum > cerebellum > cerebral cortex.

Mice given a chronic exposure to 0.3% Coal Tar in the diet

had a significantly decreased survival. Liver neoplasms were

seen in a significant dose-related trend.

When Coal Tar was applied to the backs of guinea pigs,

increases in epidermal thickness were seen.

22

Painting female rabbits with tar decreases the absolute and

relative weights of the ovaries and decreased the number of

interstitial cells in the ovary. A retrospective study of the

reproductive toxicity of Coal Tar in humans compared 23

exposed women to 59 controls and found little difference in

spontaneous abortion and congenital disorders. Conflicting

advice has been given to pregnant women — one suggestion

was to avoid use of Coal Tar to the 2nd or 3rd trimester, after

major organogenesis; another opined that the risk of

congenital abnormalities in children of women treated with

Coal Tar during pregnancy is unlikely.

When four therapeutic Coal Tar prepara tions (Zetar ®

Emulsion, Estar ®, Lavatar, and Coal Tar Solution USP) used

in the treatment of psoriasis were screened using the Ames

Salm onella/microsome mutagenicity test, all of the Coal Tar

preparations were mutagenic within the dose range tested.

Strain TA98 was the most sensitive to the mutagenic effects

of the tar. Urine and blood from patients treated with Coal

Tar were genotoxic in bacterial assays. Coal T ar was

genotoxic in plate incorporation, macro-scale fluctuation, and

microsuspension assays.

In a mammalian genotoxicity assay (Muta™ Mice), the

mutation frequency in treated animals was 2735±281x10-6

(n=3) and in control mice 171±97x10-6 (n=5), a 16 fold

increase in the number of mutations above the background

level in epidermal cells.

Coal Tar induces DNA adducts in various tissue types. A

lowest observed effect level of 0.1% Coal Tar (oral) produced

DNA adducts in mouse lung tissue.

In a carcinogenicity experiment, five groups of 95 mice were

painted with Coal Tar for four months. The percentage of

animals with tumors in the lungs was 45.1, 53.7, 50.0, 55.6,

and 57.1, respectively. After being treated with 200 :l Crude

Coal Tar in 0.2 ml acetone for 11 weeks, 100 % of the 20

female SENCAR mice had tumors. After Coal Tar was

applied to the rectum of 78 juvenile white mice for 6 months,

of the 37 animals that survived , cancer of the perianal skin

developed in 21 (56 .7%).

Out of 74 psoriasis patients, 13 reported that they were

allergic to Coal Tar; but only 2 had a positive patch test.

Several of the polycyclic aromatic hydrocarbons which make

up Coal Tar are photosensitizers and cause phototoxicity by

an oxygen dependent mechanism. Coal Tar was comedogenic

in three small clinical studies. Several published reports

describe cases of contact sensitivity to Coal Tar. Folliculitis

is associated with the prolonged use of some tars.

Follow-up studies have been performed on patients who have

received Coal Tar therapy of one form or other: 326 patients

with atopic dermatitis or neurodermatitis treated with Coal Tar

were followed for 42 years; 305 patients who received Coal

Tar and UV treatment were followed for 25 years; 206

patients receiving Coal Tar and UV treatment were followed

for 25 years; 85 psoriatic patients treated with Coal Tar and

UV treatment were compared to 385 matched controls; 719

psoriatics who received Coal Tar therapy intermittently were

studied 10 - 25 years later; 2,247 psoriatics treated with Coal

Tar were compared to 4,494 matched controls; cancers

identified from a cancer registry in 88 patients treated

extensively with Coal Tar from 1917 to 1937 were compared

to the general population. In none of these follow-up studies

was an increase in the risk of cancer found.

One retrospective study of women who used Coal Tar at the

time of their pregnancies. It was unclear if the percentage with

spontaneous abortions or births with congenital disorders was

higher in the Coal Tar group compared to controls. A case-

control study of 200 individuals with basal cell carcinoma

compared to 399 controls identified use of tar for cosmetic

purposes as a risk factor, but it was not clear how oral

methotrexate and photochemotherapy may have confounded

the results.

DISCUSSION

The data presented in this report indicate that Coal Tar can

produce adverse biological effects. While the CIR Expert

Panel believes that Coal Tar use as an antidandruff

ingredient in OTC drug preparations is adequately

addressed by FDA regulations, the Panel also believes that

the appropriate concentration of use of Coal Tar in cosmetic

formulations should be that level that does not have a

biological effect. The Panel was concerned that information

on the maximum concentration that could be used in

cosmetic formulations that would not have a biological

effect was not available.

Section 1, paragraph (p) of the CIR Procedures states that

“A lack of information about an ingredient shall not be

sufficient to justify a determination of safety.” In

accordance with Section 30(j)(2)(A) of the Procedures, the

Expert Panel informed the public of its decision that the

data on this ingredient were not sufficient for determination

whether the ingredient, under relevant condition of use, was

either safe or unsafe. Additional data needed to make a

safety assessment are product types in which Coal Tar is

used (other than as an OTC drug ingredient), use

concentrations, and the maximum concentration that does

not induce a biological effect.

CONCLUSION

The available data are insufficient to support the safety of

Coal Tar for use in cosmetic products as described in this

safety assessment.

23

REFERENCES

Alexander, J. O. and K. I. Macrosson. 1954. Squamous epitheliomaprobably due to tar ointment in a case with psoriasis. Br. Med. J.2:1089.

Ames, B. N. and L. S. Gold. 1999. Paracelsus to Parascience-TheEnvironmental Cancer Distraction.Http://marshall.pjdoland.com/article.php?id=73&print=1

Arnold, W. P. 1997. Tar. Clin. Dermatol. 15(5):739-44.

Bacelar, J. 1932. Ovarian changes in rabbits painted with tar. Annalesd’Anatomie Pathologique 9:565-568.

Berenblum, I. 1948. Liquor picis carbonis (BP), a carcinogenic agent. Br.Med. J. 2:601.

Berne, B. and T. Fischer. 1987. The UV erythema action spectra of threecoal tar preparations. Clin. Exp. Dermatol. 12(6):400-402.

Bhate, S. M. , G. R. Sharpe, J. M. Marks, S. Shuster and W. M. Ross.1993. Prevalence of skin and other cancers in patients with psoriasis.Clin. Exp. Dermatol. 18: 401-404.

Bickers, D. R. and A. Kappas. 1978. Human skin aryl hydrocarbonhydroxylase: Induction by coal tar. J. Clin. Invest. 62(5):1061-1068.

Bickers, D.R., D. Wroblewski, T. Dutta-Choudhury, et al. 1982. Inductionof neonatal rat skin and liver aryl hydrocarbon hydroxylase by coal tarand its constituents. J. Invest. Dermatol. 78(3):227-229.

Bologa, M., A. Pastuszak, N. H. Shear, et al. 1992. Dermatologic drugs inpregnancy. Clin. Dermatol. 9(4):435-351.

Bos, R. P. and F. J. Jongeneelen.1988. Nonselective and selective methodsfor biological monitoring of exposure to coal-tar products. In:Methods for Detecting DNA Damaging Agents in Humans:Applications in Cancer Epidemiology and Prevention, IARCSceintific Publications No, 89. H. Bartsch, K. Hemminki, and IKO’Neill (eds), Lyon, France, International Agency for Research onCancer, p 389-395.

Budavari, S. (ed.) 1989. The Merck Index. An Encyclopedia of Chemicals,Drugs, and Biologicals, 11th edn. Rathway, NJ: Merck & Co., Inc.2421.

Burden, A. D., H. Muston, and M. H. Beck. 1994. Intolerance and contactallergy to tar and dithranol in psoriasis. Contact Dermatitis31(3):185-186.

�erníková, M., H. Dubský, and J. Horá�ek. 1983. Detection of acridine inhuman urine after topical coal-tar treatment. J. Chromatog. 273:202-206.

Christie, G. S. and N. E. W. McCallum. 1958. The carcinogenicity ofbrown coal tar. Australasian J. Pharmacy 39(458):116-118.

Clark, A. R. and E. F. Sheretz. 1998. The incidence of allergic contactdermatitis in patients with psoriasis vulgaris. Am. J. ContactDermatitis 9(2):96-9.

Clonfero, E., M. Zordan, D. Cottica, et al. 1986. Mutagenic activity andpolycyclic aromatic hydrocarbon levels in urine of humans exposed totherapeutic coal tar. Carcinogenesis 7(5):819-23.

Clonfero, E., D. Cottica D, P. Venier, et al. 1987. Mutagenic activity andpolycyclic aromatic hydrocarbon (PAH) levels in urine of humans. In:Occupational and Environmental Chemical Hazards. V. Foa, E. A.Emmett, M. Maroni, and A. Colmbi, eds, Chichester, Ellis HorwoodLimited, 438-443.

Clonfero, E., M. Zordan, P. Venier, et al. 1989. Biological monitoring ofhuman exposure to coal tar. Urinary excretion of total polycyclicaromatic hydrocarbons, 1-hydroxypyrene and mutagens in psoriaticpatients. Int. Arch. Occup. Environ. Health 61:363-8.

Clonfero, E., F. Jongeneelen, M. Zordan, et al. 1990. Biologicalmonitoring of human exposure to coal tar. Urinary mutagenicityassays and analytical determination of polycyclic aromatichydrocarbon metabolites in urine. In: Complex Mixtures and CancerRisk, H. Vainio, M. Sorsa, and A. J. McMichael, Eds. IARC ScientificPublications No. 104, Lyon, International Agency for Research onCancer p215-222.

Committee of Revision of the United States Pharmacopeial Convention.1995. The United States Pharmacopeia 23rd edition. Rockville:United States Pharmacopeial Convention, Inc. p413.

Conover, E. A. and W. F. Rayburn. 1992. Over-the-counter drugs duringpregnancy. Drug Therapy in ObGyn. 3:45-55.

Cosmetic, Toiletry, and Fragrance Association (CTFA). 2002.Concentration of use of Coal Tar. Unpublished data submitted by theCTFA. 1

Culp, S. J. and F. A. Beland. 1994. Comparison of DNA adduct formationin mice fed coal tar or benzo[a]pyrene. Carcinogenesis 14(2):247-52.

Culp, S. J., D. W. Gaylor, W. G. Sheldon, et al. 1998. A comparison of thetumors induced by coal tar and benzo[a]pyrene in a 2-year bioassay.Carcinogenesis 19(1):117-124.

Cusano, F., M. Capozzi, and G. Errico. 1992. Allergic contact dermatitisfrom coal tar. Contact Dermatitis 27(1):51-2.

Das, M., D. R. Bickers, R. M. Santella, et al. 1985. Altered patterns ofcutaneous xenobiotic metabolism in UVB-induced squamous cellcarcinoma in SKH-1 hairless mice. J. Invest. Dermatol. 84(6):532-6.

Das, M., P. Asokan, P. S. Don, et al. 1986. Carcinogen metabolism inhuman skin grafted onto athymic nude mice: a model system for thestudy of human skin carcinogenesis. Biochem. Biophys. Res.Commun. 138(1):33-9.

Diette, K. M., R. W. Gange, R. S. Stern, et al. 1983. Coal tarphototoxicity: kinetics and exposure parameters. J. Invest. Dermatol.81(4):347-50.

Diette, K. M., R. W. Gange, R. S. Stern, et al. 1985. Coal tarphototoxicity: characteristics of the smarting reaction. J. Invest.Dermatol. 84(4):268-71.

Durkin, W., N. Sun, J. Link, et al. 1978. Melanoma in a patient treated forpsoriasis. Southern Med. J. 71(6):732-3.

Environmental Protection Agency (EPA). 1994. Toxicological Profile forPolycyclic Hydrocarbons (PAHs). Washington, DC: EnvironmentalProtection Agency:

1 Available for review from the Director, CIR, 1101 17th Street, NW, Suite310, Washington, DC 20036

24

European Economic Community.1999. EEC Cosmetics Directive76/768/EEC, as amended through the 26th Adapting CommissionDirective 2002/34/EC, Annexes 1-VII. Brussels: EEC. [Documentaccessible at: http:dg3.eudra.org/F3/home.html].

Evelo, C. T. A., J. Atema,J. H. J. Copius-Peereboom, et al.1989. Liverdamage after coal-tar treatment does not prevent induction ofglutathione S-transferases in rat liver. Arch. Toxicol. Suppl. 13: 112-116.

Everett, M. A., E. Daffer, and C. M. Coffey 1961. Coal tar and ultravioletlight. Arch. Dermatol. 84:163-166.

Everett, M. A. and J. V. Miller 1961. Coal tar and ultraviolet light. III.Cumulative effects. Arch. Dermatol. 84:937-40.

Fehling, K. A., M. A. Bono, S. M. Hays, and D. J. Paussenbach. 2000.Identification of Proposition 65 No Significant Risk Level for CoalTar Shampoos, Poster Presentation, Annual Meetings of the Societyof Toxicology, March , 2000.

Food and Drug Administration (FDA). 1982. Advanced notice ofproposed rule making, OTC drug products for the control of dandruff,seborrheic dermatitis and psoriasis. Federal Register 47(233): 54646-54684.

FDA. 1986. Dandruff, seborrheic dermatitis and psoriasis drug productsfor over-the-counter human use; tentative final monograph. FederalRegister 51(146):27346-60. Compilation of OTC drug regulations.

FDA. 1991. Final monograph, dandruff, seborrheic dermatits and psoriasisdrug products for over-the-counter human use. Federal Register 56(233): 63554-63569.

FDA. 2001a. Letter from J. Woodcock to P. Gottesfeld. Re: Docket No.

99F-1210, Comments No. CP1, C1 and C2. January 24, 2001.

FDA. 2001b. Letter from D. E. Baker to P. Gottesfeld. Re: Docket No.00F-1210, Comments No. CP1, C1 and C2. February 27, 2001.

FDA. 2002. Frequency of use of cosmetic ingredients. FDA database.Washington, DC: FDA.

Foreman, M. I., S. Picton, G. A. Lukowiecki, et al. 1979. The effect oftopical crude coal tar treatment on unstimulated hairless hamster skin.Br. J. Dermatol. 100(6):707-15.

Franssen, M. E., G. J. van der Wilt, P. C. de Jong, et al. 1999. Aretrospective study of the teratogenicity of dermatological coal tarproducts [letter]. Acta Dermatol. Venereol. 79(5):390-1.

Fysh, J. M., L. S. Andrews, L. R. Pohl, et al. 1980. Differing degrees ofcoal-tar shampoo-induced mutagenesis in the Salmonella/liver testsystem in vitro. Pharmacology 20(1):1-8.

Gennaro, A. R. 1990. Remington’s Pharmaceutical Sciences, 18th edn.Easton, PA: Mack Publishing Co. 764.

Giles, A. S., A. Seidel, and D. H. Phillips. 1996. Covalent DNA adductsformed in mouse epidermis by benzo[g]chyrsene. Carcinogenesis17(6)1331-6.

Giles, A. S., A. Seidel, and D. H. Phillips. 1997. Covalent DNA adductsformed by benzo[c]chrysene fjord-region diol epoxides reacted withDNA and polynucleotides. Chem. Res. Toxicol. 10(11):1275-84.

Godschalk, R. W., J. U. Ostertag, E. J. Moonen, et al. 1998. AromaticDNA adducts in human white blood cells and skin after dermalapplication of coal tar. Cancer Epidemiol. Biomarkers Prev.7(9):767-73.

Goeckerman, W. H. 1925. The treatment of psoriasis. Northwest MedicineXXIV (January-February): 229-231

Gonçalo, S, I. Sousa, and A. Moreno. 1984. Contact dermatitis to coal tar.Contact Dermatitis 10(1):57-8.

Gosselin, R. E., R. P. Smith, and H. C. Hodge.1984. Clinical Toxicologyof Commercial Products, 5th edn. Baltimore, MD: Williams &Wilkins. II-191.

Gottschalck, T. E. and G. N. McEwen Jr. eds. 2002. InternationalCosmetic Ingredient Dictionary and Handbook. 10th edn. Washington, DC: CTFA.

Gould, J. W., M. G. Mercurio, and C. A. Elmets. 1995. Cutaneousphotosensitivity diseases induced by exogenous agents. J. Am. Acad.Dermatol. 33(4):551-573.

Granella, M. and E. Clonfero. 1992. Sensitivity of different bacterialassays in detecting mutagens in urine or humans exposed topolycyclic aromatic hydrocarbons. Mutat. Res. 268(1):131-7.

Grimmer, G. 1990. Reply to Jongaleenen Letter to the Editor. Cancer Lett.51:175-179.

Grubler, M., R. Klein, and M. Foxx. 1970. Chemical standardization andquality assurance of whole crude coal tar U. S. P. utilizing GLCprocedures. J. Pharm. Sci. 59:830-834.

Hansen, A. M., O. M. Poulsen, and T. Menne. 1993. Longitudinal study ofexcretion of metabolites of polycyclic aromatic hydrocarbons in urinefrom two psoriatic patients. Acta Dermatol. Venereol. 73(3):188-190.

Hess, R. 1999. Safety assessment of refined coal tar used in rinse-off haircare products. J. Toxicol. Cutan. Ocular Toxicol. 18(2):161-166.

Hodgson, G. 1948 Epithelioma following the local treatment of prurius aniwith liquor picis carbonis. Br. J. Dermatol. 60:282.

Hughes, N. C., W. Pfau, and A. Hewer. 1993. Covalent binding ofpolycyclic aromatic hydrocarbon component of coal tar to DNA inmouse skin. Carcinogenesis 14(1):135-44.

Hukkelhoven, M. W. A. C., L. W. M. Vromans, F. N. A. M. Van Pelt et al.1984. In vivo induction of aryl hydrocarbon hydroxylase in humanscalp hair follicles by topical application of a commercial coal tarpreparation. Cancer Lett. 23:135-143.

Ibbotson, S. H., S. C. Stenton, and N. B. Simpson. 1995. Acute severebronchoconstriction precipitated by coal tar bandages. Clin. Exp.Dermatol. 20(1):58-9.

Illchyshyn, A., P. H. Carwright, and A. G. Smith. 1987. Contactsensitivity to newsprint: a rare manifestation of coal tar allergy.Contact Dermatits 17(1):52-53.

International Agency for Research on Cancer (IARC). 1985. Polynucleararomatic hydrocarbons, Part 3, Risk to Chemicals to Humans,Industrial Exposures...Coal Gasification, Coke Production. IARCMonographs on the Evaluation of the Carcinogenic Risk toChemicals to Humans, Vol. 34. IARC: Lyon, France.

Itchikawa, K. and S. M. Baum. 1925. The rapid production of cancer inrabbits by coal tar. J. Cancer Res. 9:85-104.

25

Jackson, E. M. 2003. Coal Tar: Use, Genotoxicity, Risk Assessment andEpidemiology, presented to the Cosmetic Ingredient Review ExpertPanel, February 6, 2003. 1

Jemec, G. B. E. and A. Øserlind. 1994. Cancer in patients treated withcoal tar: a long term follow up study. J. Europ. Acad. Dermatol.Venereol.. 3:153-156.

Jacob J., H. Brune, G. Gettbarn et al. 1989. Urinary and faecal excretionof pyrene and 1-hydroxypyrene by rats after oral, intraperitoneal,intratracheal and intrapulmonary application. Cancer Lett. 46:14-20.

Jones, S. K., R. M. Mackie, D. J. Hole, et al. 1985. Further evidence of thesafety of tar in the management of psoriasis. Br. J. Dermatol. 113:97-101.

Jongeneelen, F. J., R. P. Bos, R. B. Anzion, et al. 1986. Biologicalmonitoring of polycyclic aromatic hydrocarbons. Metabolites in urine.Scand. J. Work Environ. Health 12(2):137-43.

Jongeneelen, F. J., R. P. Bos, and P. T. Henderson. 1988. Metabolites ofpolycyclic aromatic hydrocarbons in urine of exposed workers.Toxicological Environ. Chem. 16(4):295-307.

Jorstad, L. H. 1923. A study of the behavior of coal tar on tissues.Proceed. Soc. Exp. Biol. Med. 21:67-70.

Jorstad, L. H. 1925. The behavior of coal tar in adult and embryonictissue. J. Cancer Res. 9:232-253.

Kaaber, K. 1976. Occurrence of malignant neoplasms in patients withatopic dermatitis. Acta Dermatovener (Stockholm). 56:445-447.

Kaidbey, K. H. and A. M. Kligman. 1974a. A human model of coal taracne. Arch. Dermatol. 109(2):212-215.

Kaidbey, K. H. and A. M. Kligman. 1974b. Topical photosensitizers.Influence of vehicles on penetration. Arch. Dermatol. 110(6):868-870.

Kaidbey, K. H. and A. M. Kligman. 1975. Further studies ofphotoaugmentation in humans: phototoxic reactions. J. Invest.Dermatol. 65(5):572-5

Kaidbey, K. H. and A. M. Kligman. 1977. Clinical and histological studyof coal tar phototoxicity in humans. Arch. Dermatol. 113(5):592-5.

Kirby, P. E. 2003. Review of the Genotoxicity of Coal Tar. Report toJackson Research Associates, Inc. Sumner, WA. January 24, 2003. 1

Kligman, A. M. and L. H. Kligman. 1994. Carcinogens showcomedogenic activity: a potential animal screen for tumorigenicsubstances. Cancer Lett. 87(2):171-8.

Kochevar, I. E., R. B. Armstrong, J. Einbinder, et al. 1982. Coal tarphototoxicity: active compounds and action spectra. Photochem.Photobiol. 36(1):65-70.

Koerber, Jr., W. A., N. M. Price, and W. Watson. 1978. Coexistentpsoriasis and bullous pemphigoid: a report of six cases. Arch.Dermatol. 114(11):1643-6.

Koganti, A., R. Siingh, K. Rozett, et al. 2000. 7H-Benzo(c)fluorene: amajor DNA adduct forming component of coal tar. Carcinogenesis21(8):1601-1609.

Kokkini, G. and H. Giotaki. 1984. Pancytopenia associated with coaltreatment. Haematologica 69(4):454-7.

Koppers, Company, Inc. (no date). Ames Salmonella/microsome assay ofseven coal tar distillate fractions with attachments. NTIS Report No.OTS0516153.

Kosuge, T., H. Zenda, N. Nukaya, et al. 1982. Isolation and structuraldetermination of mutagenic substances in coal tar. Chem. Pharm.Bull. 30:1535-1538.

Kroon, S. 1983. Standard photopatch testing with Waxtar, para-aminobenzoic acid, potassium dichromate and basalm of Peru.Contact Dermatitis 9(1):5-9

Landro, A. D., R. Valsecchi, and T. Cainelli. 1992. Contact allergy todithranol. Contact Dermatitis 26: 49-50.

Larko, O. and G. Swanbeck. 1982. Is UVB treatment of psoriasis safe? Astudy of extensively UVB treated psoriasis patients compared with amatched control group. Acta Dermatovener (Stockholm). 62:507-512.

L’Epee, P., H. J. Lazarini, and J. Doignon. 1983. Encyclopaedia ofOccupational Health and Safety, Vol. 2 p 2147-2149.

Lerner, M. R. and A. B. Lerner. 1960. Dermatologic Medications, 2nd Ed.P169-173. Year Book Publishers, Chicago, Illinois.

Lewis, R. J. Sr. 1993. Hazardous Chemicals Desk Reference, 3rd edn. NewYork, NY: Van Nostrand Reinhold. 341-342

Lin, A. N., K. Moses. 1985. Tar revisited. Int. J. Dermatol. 24(4):216-8.

Litofsky, I. B. 1999. A review of analytical methodology for thedetermination of polycyclic aromatic hydrocarbons in coal tarproducts. J. Cutan. Ocular Toxicol. 18: 151-156.

Lowe, N. J., J. Breeding, and M. S. Wortzman. 1982. Thepharmacological variability of crude coal tar. Br. J. Dermatol.107:475-479.

Maughan, W. Z., S. A. Muller, H. O. Perry, et al. 1980. Incidence of skincancers in patients with atopic dermatitis treated with coal tar. A 25-year follow-up study. J. Am. Acad. Dermatol. 3(6):612-5.

McGarry, G. W. and J. R. Robertson. 1989. Scrotal carcinoma followingprolonged use of crude coal tar ointment. Br. J. Urol. 63(2):211.

Merk, H. F., H. Mukhtar, I. Kaufmann et al. 1987. Human hair folliclebenzo[a]pyrene and benzo[a]pyrene 7,8-diol metabolism: effect ofexposure to a coal-tar containing shampoo. J. Invest. Dermatol.88(1):71-6.

Mills, O. H., M. Porte, and A. M. Kligman. 1978. Enhancement ofcomedogenic substances by ultraviolet radiation. Br J Dermatol98(2):145-50.

Ministry of Health, Labor, and Welfare (MHLW). March 2001a.Unofficial translation of MHW Ordinance No. 331, Attached Table 1[Negative List]. Ministry of Health, Labor and Welfare,Pharmaceutical and Medical Safety Bureau, Inspection and GuidanceDivision, 2-2, 1-chome, Kasumigaseki, Chiyoda-ku, Tokyo 100-8045,Japan.

MHLW. March 2001b. Unofficial translation of MHW Ordinance No.331, Attached Table 2 [Restricted List]. Ministry of Health, Labor,and Welfare, Pharmaceutical and Medical Safety Bureau, Inspectionand Guidance Division, 2-2, 1-chome, Kasumigaseki, Chiyoda-ku,Tokyo 100-8045, Japan.

26

Mukhtar, H. and D. R. Bickers. 1982. Evidence that coal tar is a mixedinducer of microsomal drug-metabolizing enzymes. Toxicol. Lett.11(3-4):221-227.

Mukhtar, H., P. Asokan, M. Das, et al. 1986c. Benzo(a)pyrene diolepoxide-I-DNA adduct formation in the epidermis and lung ofSENCAR mice following topical application of crude coal tar. CancerLett. 33(3):287-94.

Mukhtar, H., M. Das, and D. R. Bickers. 1986a. Skin tumor initiatingactivity of therapeutic crude coal tar as compared to other polycylicaromatic hydrocarbons in SENCAR mice. Cancer Lett. 31(2):147-51.

Mukhtar, H., B. J. DelTito Jr., P. M. Matgouranis, et al. 1986b. Additiveeffects of ultraviolet B and crude coal tar on cutaneous carcinogenmetabolism: possible relevance to the tumorigenicity of theGoeckerman regimen. J. Invest. Dermatol. 87(3):348-53.

Murphy, J. B. and E. Sturm. 1925. Primary lung tumors in mice followingthe cutaneous application of coal tar. J. Exp. Med. 42:693-700.

OEHHA 2003. State of California Environmental Protection AgencyOffice of Environmental Health Hazard Assessment (OEHHA) SafeDrinking Water and Toxic Enforcement Act of 1986: Chemicalsknown to the state to cause cancer or reproductive toxicity, July 11,2003.http://www.oehha.org/prop65/prop65_list/files/71103LISTA.pdf

Paleologo, M., F. J. van Schooten, S. Pavanello, et al. 1992. Detection ofbenzo[a]pyrene-diol-epoxide-DNA adducts in white blood cells ofpsoriatic patients treated with coal tar. Mutat. Res. 281(1):11-6.

Pavanello, S., D. Favretto, F. Brugnone, et al. 1999. HPLC/fluorescecedetermination of anti-BPDE-DNA adducts in mononuclear whiteblood cells from PAH-exposed humans. Carcinogenesis 20(3):431-5.

Pavanello, S. and A. G. Levis. 1992. Coal tar therapy does not influence invitro benzo[a]pyrene metabolism and DNA adduct formation inperipheral blood lymphocytes of psoriatic patients. Carcinogenesis13(9):1569-73.

Pavanello, S. and A. G. Levis. 1994. Human peripheral blood lymphocytesas a cell model to evaluate the genotoxic effect of coal tar treatment.Environ. Health Perspec. 102:95-9.

Perov, O. V. 1972. Changes in antioxidative activity of cells and functionsof the nucleus by the action of subtoxic doses of phenol-pyridinemixtures from coal tar. Bull. Exp. Biol. Med. 73:267-270.

Person, J. R. and R. S. Rogers III. 1976. Bullous pemphigoid andpsoriasis: does subclinical bullous pemphigoid exist? Br. J. Dermatol.95(5):535-40.

Pfau, W., S. Lecoq, and N. C. Hughes. 1993. Separation of 32P-labellednucleoside 3'5'-bisphosphate adducts by HPLC. IARC Sci. Pub.(124):233-42

Phillips, D. H. and A. J. Alldrick. 1994. Tumorigenicity of a combinationof psoriasis therapies. Br. J. Cancer 69(6):1043-5.

Pickering, R. W. 1999. A toxicological review of polycyclic aromatichydrocarbons. J. Cutan. Ocular Toxicol. 18(2):101-135.

Pinsky, C. and R. Bose. 1988. Pyridine and other coal tar constituents asfree radical-generating environmental neurotoxicants. Mol.Cell.Biochem. 84(2):217-222.

Pion, I. A. , K. L. Koenig and H. W. Lim. 1995. Is dermtologic usage ofcoal tar carcinogenic? Dermatologic Surgery. 21:227-231.

Pittelkow, M. R., H. O. Perry, and S. A. Muller. 1981. Skin cancer inpatients with psoriasis treated with coal tar. A 25-year follow-upstudy. Arch. Dermatol. 117(8):465-8.

Registry of Toxic Effects of Chemical Substances (RTECS). 2001. Coaltar entries. RTECS database. Bethesda, MD: National Library ofMedicine.

Riboldi, A., P. D. Pigatto, M. O. Innocenti, et al. 1986. Contact dermatitisto coal tar in psoraisis. Contact Dermatitis 14(3):187-188.

Ritschel, W. A., P. E. Ring, and E. G. Siegel. 1975. Influence of coal taron hair growth in rabbits. Sci. Pharm. 43:73-80.

Santella, R. M., M. G. Nunes, R. Blaskovic, et al 1994. Quantitation ofpolycyclic aromatic hydrocarbons, 1-hydroxypyrene, andmutagenicity in urine of coal tar-treated psoriasis patients anduntreated volunteers. Cancer Epidem. Biomarkers Prevention3(2):137-140.

Santella, R. M., F. P. Perera, T. L. Young, et al. 1995. Polycyclic aromatichydrocarbon-DNA and protein adducts in coal tar treated patients andcontrols and their relationship to glytathione S-transferase genotype.Mutat. Res. 334(2):117-24.

Saperstein, M. D. and L. A. Wheeler. 1979. Mutagenicity of coal tarpreparations used in the treatment of psoriasis. Toxicol. Lett. 3:325-29.

Sarkany, I. and P. M. Gaylarde. 1976. Effect of coal tar fractions onguinea-pig and human skin. Clin. Exp. Dermatol. 1:51-58.

Sarto, F., M. Zordan, R. Tomanin, et al. 1989. Chromosomal alterations inperipheral blood lymphocytes, urinary mutagenicity and excretion ofpolycyclic aromatic hydrocarbons in six psoriatic patients undergoingcoal tar therapy. Carcinogenesis 10(2):329-334.

Schoket, B., A. Hewer, P. L. Grover, et al. 1988a. Covalent binding ofcomponents of coal tar, creosote and bitumen to the DNA of the skinand lungs of mice following topical application. Carcinogenesis9(7):1253-8.

Schoket, B., A. Hewer, P. L. Grover, et al. 1988b. Formation of DNAadducts in human skin maintained in short-term organ culture andtreated with coal-tar, creosote or bitumen. Int. J. Cancer 42(4):622-6.

Schoket, B., I. Horkay I, Á. Kósa, et al. 1990. Formation of DNA adductsin the skin of psoriasis patients, in human skin in organ culture, andin mouse kin and lung following topical application of coal-tar andjuniper tar. J. Invest. Dermatol. 94: 241-6.

Seelig, M. G. and Z. K. Cooper. 1933. Light and tar cancer: anexperimental study with a critical review of the literature on light as acarcinogenic factor. Surgery, Gynecology and Obstetrics 56:752-761.

Shabad, L. M. 1927. Coal tar as a carcinogen when applied to the rectumof white mice. Vestnik Rentgenologii i Radiologii 5:171-179.

Simon, C. R. and R. Brandt. 1953. Eczematous hypersensitivity to coaltar. AMA Arch. Dermatol.Syphilol. 67:584-586.

Simonds, J. P. and J. S. Curtis. 1935. Lesions induced in the lungs byintravenous injection of tar. Arch. Pathol. 19(3):287-302.

Starke, J. C. and O. F. Jillson. 1961. Photosensitization to coal tar. Acause of psoriatic erythroderma. Arch. Dermatol. 84:935-936.

Stone, O. J. and C. J. Willis. 1969. The effect of tar on infection. Toxicol.Appl. Pharmacol. 15:677-678.

27

Storer, J. S., I. DeLeon, L. E. Millikan, et al. 1984. Human absorption ofcrude coal tar products. Arch. Dermatol. 120(7):874-7.

Tenant, R. W., B. H. Margolin, M. D. Sheby et al. 1987. Prediction ofchemical carcinogenicity in rodents from in vitro genetic toxicityassays. Science. 236:933-941.

Thein, N., P. Moller, H. Amtoft, et al. 2000. A strong genotoxic effect inmouse skin of a single painting of coal tar in hairless mice and inMuta™Mouse. Mutat. Res. 468(2):117-24.

Van Cantfort, J., T. Lorand, J. E. Gielen, et al. 1986. Human epidermalblister: a convenient tissue for toxicological and genetic studies ofbenzo(a)pyrene metabolism. Arch. Dermatol. Res. 278(4):324-8.

VanRooij, J. G. M., J. H. C. De Roos, M. M. Bodelier-Bade, et al. 1993.Absorption of polycyclic aromatic hydrocarbons through human skin:Differences between anatomical sites and individuals. J. Toxicol.Environ. Health 38(4):355-368.

VanRooij, J. G. M., E. Vinke, J. De Lange, et al. 1995. Dermal absorptionof polycyclic aromatic hydrocarbons in the blood-perfused pig ear. J.Appl. Toxicol. 15(3):193-200.

van Schooten, F.-J., E. J. C. Moonen, E. Rhijnsburger, et al. 1994. Dermaluptake of polycyclic aromatic hydrocarbons after hairwash with coal-tar shampoo. Lancet 344(8935):1505-6.

Viau, C., A. Vyskocil. 1995. Patterns of 1-hydroxypyrene excretion involunteers exposed to pyrene by the dermal route. Sci. Total Environ.163(1-3):187-90.

Vlajinac, H. D., B. J. Adanja, Z. F. Lazar, et al. 2000. Risk factors forbasal cell carcinoma. Acta Oncol. 39(5):611-6.

Warshawsky, D., W. Barkley, and E. Bingham. 1993. Factors affectingcarcinogenic potential of mixtures. Fundam. Appl. Toxicol.20(3):376-82

Watson, A. F. 1935. Comparative studies on carcinogenesis in rats. Am. J.Cancer 25:753-762.

Watson, A. F. and E. Mellanby. 1930. Tar cancer in mice: I. Thetechnique of the comparative experiment. Br. J. Exp. Pathol. 11:267-281.

Weyand, E. H., Y. Wu, S. Patel, et al. 1991. Urinary excretion and DNAbinding of coal tar components in B6C3F1 mice following ingestion.Chem. Res. Toxicol. 4(4):466-73.

Wheeler, L. A., M. D. Saperstein, and N. J. Lowe. 1981. Mutagenicity ofurine from psoriatic patients undergoing treatment with coal tar andultraviolet light. J. Invest. Dermatol. 77(2):181-5.

Wilkinson, J. and R. Moore (eds). 1982. Harry’s Cosmetology, 7th ed.New York: Chemical Publishing. 499.

Wright, C. W., D. W. Later, R. A. Pelroy, et al. 1985. Comparativechemical and biological analysis of coal tar-based therapeutic agentsto other coal-derived materials. J. Appl. Toxicol. 5(2):80-88.

Wright, M. C., A. Kaufhold, F. Hevert, et al. 1992. Studies on the possiblenephrotoxicity of a coal tar-containing dermatic. Hautarzt 43:483-486.

Yamagiwa, K. and K. Ichikawa. 1917. Experimental study of thepathogenesis of carcinoma. J. Cancer Res. 3:1-29.

Yoshikawa, K. 1996. Anomalous nonidentity between Salmonellagenotoxicants and rodent carcinogens. Environ. Health Perspect.104:40-46.

Zhang, Y. J., Y. Li, V. A. DeLeo, et al. 1990. Detection of DNA adductsin skin biopsies of coal tar-treated psoriasis patients:immunofluorescence and 32P postlabeling. Skin Pharmacol.3(3):171-9.