objective data collection for roofing industry exposures ... · under 29 cfr §1926.1153(c), osha...

August 2019

Objective Data Collection for Roofing Industry Exposures under 29 CFR 1926.1153

On March 25, 2016, the Occupational Safety and Health Administration (OSHA) released a final

rule on worker exposure to respirable crystalline silica (RCS). The rule became effective June 23,

2016, but enforcement initially was delayed until June 23, 2017, and finally initiated Sept. 23, 2017.

According to OSHA, about 2.3 million workers are exposed to RCS in the workplace—respirable

silica means inhaled particles 10 microns in size or less that can get into critical lung areas and cause

health problems. The at-risk workforce comprises about 2 million construction workers who drill,

cut, crush or grind silica-containing materials such as concrete and stone and 300,000 workers in

general industry operations such as brick manufacturing, foundries and hydraulic fracturing. The

common construction tasks cited by OSHA as involving exposure to RCS may not be performed

extensively by roofing workers, but this objective data compilation has been established to assist

contractors in minimizing roofing worker exposure.

Silica refers to the chemical compound silicon dioxide (SiO2) the most common form of which is

quartz. Sand, a key component in many building products like mortar, clay and concrete tiles or

pavers and brick, mainly is composed of silica in the form of quartz. Hazards develop when

materials containing silica are cut, drilled or ground in a way that produces respirable silica. This

most often is done with powered saws or grinders with diamond blades or silicon carbide cut wheels

that produce airborne particles that can be inhaled. The danger results when the smallest of particles

(those that are respirable) penetrate to the gas exchange area of the lungs; larger particles do not

travel that deep into the lungs and are purged by natural actions of the body. The respirable particles

remain in the lungs and permanently scar lung tissue making breathing increasingly more difficult—

an occupational disease known as silicosis that often does not manifest itself until many years after

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exposures. According to the American Lung Association, silicosis also increases the risk of other

lung issues like tuberculosis, lung cancer and chronic bronchitis.

The construction regulation

Following are key features provided in the construction rule:

• Establishment of an action level and a permissible exposure limit (PEL) for worker exposures

• Specified exposure control methods for construction tasks listed in what OSHA refers to as Table 1 that eliminate the requirement for initial exposure monitoring

• The requirement for a written exposure control plan

• Medical surveillance for workers required to use a respirator for 30 or more days in a year

• Silica hazard communication to workers

• Use of objective data to assess worker exposure to silica

• A specific compliance date for the construction industry

Action level and PEL

Under the OSHA rule, an employer must ensure no worker is exposed to a RCS concentration more

than the PEL of 50 micrograms per cubic meter of air calculated as an eight-hour time weighted

average. The employer also is obliged to assess the exposure of any worker who is or may reasonably

be expected to be exposed to a level of RCS at or above the action level of 25 micrograms per cubic

meter of air calculated as an eight-hour time-weighted average. Performing air monitoring of

workers to assess the exposure to RCS likely is the most burdensome requirement in the regulation

for employer compliance. However, two other elements of the rule may be relied on to minimize the

administrative burdens and financial impact of the rule while keeping workers safe: the provision for

objective data and use of the specified exposure control methods under Table 1.

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Table 1

Under 29 CFR §1926.1153(c), OSHA sets out specified exposure control methods for a variety of

construction tasks. For those tasks set out in Table 1, if the employer implements the engineering

controls and respiratory protection listed in Table 1 for a specific task, the employer will be

considered in compliance with the rules for exposure to RCS under the rule [29 CFR

§1926.1153(e)(3)]. Initial exposure monitoring would not be required. As an example, Table 1

requires an integrated water delivery system that continuously feeds water to the blade of a handheld

power saw used to cut silica-containing material. For outdoor use of four hours or less with such a

saw, Table 1 does not require a respirator be worn by the operator in conjunction with the water

delivery to the blade. However, if cutting exceeds four hours, a respirator with an assigned

protection factor (APF) of 10 also must be used with the water delivery system. Filtering face piece

respirators (dust masks) are available with an APF of 10 and half-mask or full-face mask air-

purifying respirators with an APF of 10 or greater are suitable alternatives to dust masks but also are

cumbersome and restrict visibility, which is a liability for workers on roofs because such masks may

increase the possibility of other injuries. The use of water to control dust is an area of substantial

concern for worker safety particularly when workers are at elevation on sloped surfaces even when

the slope is relatively low. A greater likelihood of slip, trip or fall injuries as a result of water on a

work surface is a natural consequence of the required engineering controls.

Another Table 1 task listed by OSHA is the use of a handheld grinder for mortar removal, for

example, to facilitate counterflashing installation in the roofing industry. To comply with the

engineering controls, the grinder must be equipped with a shroud and dust-collection system

operated according to the manufacturer’s instructions. OSHA specifies the minimum airflow, filter

efficiency and type under Table 1 for compliance. In addition, an operator using a grinder with the

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described dust-collection attachment must wear a respirator with an APF of 10 when grinding work

is performed for four hours or less and a respirator with an APF of 25 when grinding is performed

for more than four hours. The National Institute for Occupational Safety and Health (NIOSH) lists

two types of APF 25 respirators in its selection logic: any powered air-purifying respirator equipped

with a hood or helmet and a high-efficiency (HEPA) filter and any continuous flow supplied-air

respirator equipped with a hood or helmet. Extending the time an operator uses a grinder for mortar

joints in excess of four hours triggers required use of the more efficient yet cumbersome respirator,

which also may increase the likelihood of falls or other injuries.

Medical surveillance

The medical surveillance requirement under the rule is tied to the days a worker must use a

respirator. If respirator use will be required on 30 or more days per year, a contractor must make

sure several medical examinations and procedures take place. For example, an initial examination

must focus on a worker’s medical and work history, a physical exam, chest X-ray, pulmonary

function test and tuberculosis test. OSHA requires an initial examination as a baseline evaluation to

be performed within 30 days after the worker’s initial assignment. Periodic examinations covering

the areas listed under the initial examination protocol must be conducted at least every three years or

more frequently if recommended by the physician or other licensed health care professional

(PLHCP).

A contractor must make sure the PLHCP is informed of the worker’s duties as they relate to RCS

exposure; the anticipated levels of occupational exposure to RCS that the worker may expect and

any current or past exposures; a description of personal protective equipment used or to be used by

the worker; and information from work-related medical exams previously provided to the worker

and currently under the control of the employer.

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A contractor must obtain a written medical opinion from the PLHCP within 30 days of the medical

examination of the worker and must ensure the worker receives a copy of the written medical

opinion from the PLHCP within that same 30 days.

Worker exposure assessment and objective data

Under 29 CFR §1926.1153(d), for construction tasks not listed in Table 1 or where the employer

does not fully and properly implement the engineering controls, work practices and respiratory

protection described in Table 1, the employer must ensure no employee is exposed to an airborne

concentration of RCS more than 50 micrograms per cubic meter of air as an eight-hour time-

weighted average. An employer must assess the exposure of any worker who is or may be reasonably

expected to be exposed to RCS at or above the action level using either of two regulatory options:

the performance option or scheduled monitoring option.

The performance option allows assessment of the eight-hour time-weighted exposure based on any

combination of air-monitoring data or objective data sufficient to accurately characterize the worker

exposure to RCS. The scheduled monitoring option requires the employer to perform initial

monitoring based on one or more personal breathing zone air samples of workers by shift, job

classification and work area. Additional subsequent required monitoring depends on the nature of

the initial results with respect to the action level and PEL under the rule. Regardless of the option

used by the employer, worker exposures must be reassessed whenever a change in the production,

process, control equipment, personnel or work practices may reasonably be expected to result in

exposures at or above the action level. This is true also if the employer has reason to believe

exposures at or above the action level have occurred.

Objective data under the performance option means:

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“…information, such as air monitoring data from industry-wide surveys or calculations based on the composition of a substance, demonstrating employee exposure to respirable crystalline silica associated with a particular product or material or a specific process, task, or activity. The data must reflect workplace conditions closely resembling or with a higher exposure potential than the processes, types of material, control methods, work practices, and environmental conditions in the employer’s current operations.”

OSHA notes reliance on objective data is intended to provide the same degree of assurance that air

monitoring of worker exposures through personal breathing samples does; so it comes with a

similar, specific recordkeeping requirement as air monitoring data. A contractor must maintain a

record of silica-containing material; source of the objective data; test protocol and results of testing;

description of the process, task or activity on which the objective data were based along with other

data relevant to the foregoing or the exposures on which the objective data were based. Because

OSHA views objective data similar to employee exposure records, the rule requires the data be

maintained for at least 30 years.

NRCA’s compilation of objective data is intended to provide a source of exposure data for roofing

tasks that may involve contact with silica as suggested primarily from information found in Section 3

of manufacturers safety data sheets (SDSs) for the products being handled. In addition, data has

been captured for other tasks that may or may not be listed in Table 1 and for which silica exposure

was possible based on assumptions about the nature of the task and the material being disturbed.

The goal of the collection is to provide dependable, quality data to help roofing contractors protect

their workers from harmful exposures to RCS.

August 2019

Sampling Results

RCS and Total Respirable Particulate or Dust

Various Roofing Industry Tasks September 7, 2018

August 2019

Asphalt shingle removal project #1701

Date: July 5, 2017

Location: Munster, IN

Structure type: Church

Project description: Removal of 5,000 square feet of approximately 25 year old, three-tab shingle removal using hand tools

Lab analysis of removed material: 9.9% quartz

Crew members sampled: 5.

Sample results for RCS in micrograms per cubic meter of air during removal phase:

9.0 µg

9.2 µg

9.3 µg

9.4 µg

9.4 µg

RCS as a full shift TWA:

9.2 µg

9.3 µg

9.3 µg

9.4 µg

9.4 µg

Sample results for respirable particulate in milligrams per cubic meter of air during removal phase:

0.090 mg

0.092 mg

0.093 mg

0.094 mg

0.094 mg

August 2019

Respirable particulate as a full shift TWA:

0.092 mg

0.093 mg

0.093 mg

0.094 mg

0.094 mg

August 2019

Asphalt shingle installation project #1702

Date: July 6, 2017



Project description: Installation of ice and water barrier and laminated asphalt shingles on 5,000 square foot roof area

Products installed: Carlisle WIP® 100 water and ice protection and Certainteed Landmark® asphalt shingles


Sample results for RCS in micrograms per cubic meter of air during installation phase:

9.4 µg

9.5 µg

9.4 µg

9.4 µg

9.4 µg


9.2 µg

9.3 µg

9.3 µg

9.4 µg

9.4 µg

Sample results for respirable particulate in milligrams per cubic meter of air during installation phase:

0.094 mg

0.095 mg

0.094 mg

0.094 mg

0.094 mg

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0.092 mg

0.093 mg

0.093 mg

0.094 mg

0.094 mg

August 2019


Date: September 6, 2017

Location: Fairfield, OH

Structure type: Residence

Project description: 1,400 square feet of asphalt shingle and underlayment removal using hand tools

Lab analysis of removed material: 9.9% quartz


Sample results for RCS in micrograms per cubic meter of air during the removal phase:

18.0 µg

17.0 µg

19.0 µg

18.0 µg

22.0 µg


10 µg

11 µg

11 µg

11 µg

19 µg

Sample results for respirable particulate in milligrams per cubic meter of air during the removal phase:

0.18 mg

0.17 mg

0.19 mg

0.18 mg

0.32 mg

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<0.10 mg

<0.11 mg

<0.11 mg

<0.11 mg

<0.14 mg

August 2019



Location: Fairfield, OH


Project description: Installation of synthetic underlayment, water barrier and laminated asphalt shingles on 1,400 square foot roof area using pneumatic nail guns.

Products installed: Atlas Summit® 60 Synthetic underlayment; Atlas Weathermaster® granular self-adhesive ice and water barrier; Atlas StormMaster® shingles.


Sample results for RCS in micrograms per cubic meter of air during the installation phase:

7.3 µg

8.6 µg

7.5 µg

7.7 µg

18.0 µg


10 µg

11 µg

11 µg

11 µg

19 µg

Sample results for respirable particulate in milligrams per cubic meter of air during the installation phase:

0.073 mg

0.086 mg

0.075 mg

0.077 mg

0.073 mg

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<0.10 mg

<0.11 mg

<0.11 mg

<0.11 mg

<0.14 mg

August 2019



Location: Portland, OR


Project description: 1,000 square feet of asphalt shingle and underlayment removal using hand tools

Crew members sampled: 2

Sample results for RCS in micrograms per cubic meter of air during removal phase:

33.0 µg

11.0 µg


21.0 µg

11.0 µg

Sample results for respirable particulate in milligrams per cubic meter of air during removal phase:

1.2 mg

<0.11 mg


0.64 mg

0.11 mg

August 2019



Location: Portland, OR


Project description: Installation of roofing felt and asphalt shingles on approximately 1,000 square foot roof area using pneumatic nail guns.

Product installed: GAF Timberline HD® asphalt shingles


Sample results for RCS in micrograms per cubic meter of air during installation phase:

12.0 µg

12.0 µg


21.0 µg

11.0 µg

Sample results for respirable particulate in milligrams per cubic meter of air during installation phase:

<0.12 mg

<0.12 mg


0.64 mg

0.11 mg

August 2019

Modified bitumen removal and installation project #1721

Date: August 1, 2017



Project description: Removal of granulated modified bitumen cap sheet and asphalt underlayment and installation of Certainteed Black Diamond self-adhering base sheet and torch -applied Certainteed GTA cap sheet (Desert Tan).


Sample results for RCS in micrograms per cubic meter of air:

<10 µg

<7.1 µg

<7.1 µg

<10 µg

<7.2 µg


<5 µg

<5.2 µg

<3.6 µg

<5.1 µg

<5.2 µg

Sample results for respirable particulate in milligrams per cubic meter of air:

<0.10 mg

<0.071 mg

<0.071 mg

<0.10 mg

<0.072 mg

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<0.05 mg

<0.052 mg

<0.036 mg

<0.051 mg

<0.052 mg

August 2019

Modified bitumen installation project #1723


Location: Madison, WI

Structure type: School

Project description: Installation of 4,000 square feet of torch-applied SBS modified bitumen

Product installed: Siplast Paradiene® 20 PR TG.


Sample results for RCS in micrograms per cubic meter of air as full shift TWA:

4.6 µg

4.7 µg

4.8 µg

5.0 µg

4.6 µg

4.7 µg

Sample results for respirable particulate in milligrams per cubic meter of air as full shift TWA:

0.046 mg

0.047 mg

0.081 mg

0.050 mg

0.046 mg

0.047 mg

August 2019

BUR/Modified removal and modified bitumen and gypsum roof board installation project #1725

Date: December 15, 2017

Location: Berwyn, IL

Structure type: Bank

Project description: Removal of a gravel-surfaced BUR with modified bitumen roof flashings and installation of approximately 450 square feet of gypsum roof board and modified bitumen base and cap sheets. Tools used included a powered roof cutter, gas axe, grinder, roof spade, prybar, crowbar, razor knives, hammers, roofing torch, brooms and wheelbarrows. The bulk sample of the roofing material removed was analyzed to have <0.24 % quartz and <0.24% Cristobalite and <0.96% Tridymite.

Product installed: Densdeck® gypsum roof board; Johns-Manville SBS modified bitumen base sheet and Johns-Manville Dynaweld Cap 250 FR.


Sample results for RCS in micrograms per cubic meter of air as full shift TWA:

<4.4 µg

<4.4 µg

<4.4 µg

<4.4 µg

<4.4 µg

Sample results for respirable dust in milligrams per cubic meter of air as full shift TWA:

0.14 mg

0.096 mg

0.064 mg

0.044 mg

0.11 mg

August 2019

Built-up roofing removal project #1744


Location: Clackamas, OR


Project description: 1,500 square feet of built up roofing system removal (half day) using powered roof cutter, shovels, brooms and wet/dry vacuum



23 µg

10 µg

10 µg


17 µg

10 µg

10 µg


1.8 mg

0.34 mg

0.25 mg


1.31 mg

0.57 mg

0.18 mg

August 2019

Built-up roofing installation project #1745


Location: Clackamas, OR


Project description: 1,000 square feet of built up roofing system installation (half day)

Product installed: Johns Manville Dynabase®



11 µg

11 µg

11 µg


17 µg

10 µg

10 µg


0.81 mg

0.8 mg

0.11 mg


1.31 mg

0.57 mg

0.18 mg

August 2019

Built-up roofing removal and installation project #1746

Date: October 10, 2017

Location: Mendota Heights, MN

Structure type: Commercial structure

Project description: 3,000 square feet of built up roofing system removal (half day). Workers removed a built-up roof system with a motorized roof cutter, shovels and wheelbarrows and debris was loaded into a dumpster using a crane. Fine asphalt debris was cleaned up using a gas-powered gravel sweeper. After clean-up, two workers drilled approximately 100 holes into concrete using a ¼-inch drill bit to a depth of 2-3 inches. Workers then installed rigid insulation, a cover board, Grace Ice & Water Shield, Johns Manville GlasPly®IV using Trumbull Trulo® Low Odor Asphalt and Johns Manville Dynaflex SBS Mineral Surfaced Flashing Sheet.



9.1 µg

9.4 µg

12 µg


7.3 µg

7.5 µg

9.6 µg


0.17 mg

0.15 mg

0.26 mg


0.14 mg

0.12 mg

0.21 mg

August 2019

Built-up roofing removal and installation project #1747


Location: Milwaukee, WI

Structure type: Public utility building

Project description: Approximately 1,000 square feet of built up roofing system was removed and a new built-up roof system installed. Workers removed a built-up roof system with a roof cutter, roof plow and manual tools. Fine asphalt debris was cleaned up using a blower. After clean-up, workers fastened Densdeck® gypsum roof board into the metal deck over which a two-ply roofing felt was installed followed by use of a chain mop to flood coat the two-ply system.

Product installed: Johns Manville GlasPly® Premier



<8.5/14 µg

<9.3/15 µg

<8.1/14 µg


<11.0 µg

<11.0 µg

<10.0 µg


<0.085/0.14 mg

<0.093/0.15 mg

<0.081/0.14 mg


<0.106 mg

<0.115 mg

<0.103 mg

August 2019

Sheet metal and flashing installation project #1766


Location: Chicago, IL

Structure type: Apartment building

Project description: Drilling and sawing into concrete and masonry to install 100’ of base tie-in and 50’ aluminum termination bar; drilled for fasteners every 12 inches (approximately 150 holes)


Eight-hour TWA concentration for RCS in micrograms per cubic meter of air:

5.8 µg

5.7 µg

Eight-hour TWA concentration for respirable dust in milligrams per cubic meter of air:

0.13 mg

0.095 mg

August 2019

Fastener installation into concrete for waterproofing project #1767


Location: Fridley, MN


Project description: Drilling of approximately 200 holes in concrete walls to insert fasteners for installation of approximately 1,000 square feet of waterproofing membrane. Holes were ¼-inch in diameter and drilled to a depth of 2 inches. The drill was not equipped with dust collection.



5.8 µg

10.0 µg

16.5 µg


5.8 µg

10 µg

16.5 µg


0.26 mg

0.15 mg

0.13 mg


0.26 mg

0.15 mg

0.13 mg

August 2019

Hammer drilling into concrete wall for insulation and membrane attachment #1768


Location: Minneapolis, MN


Project description: One worker drilled approximately 80 holes in concrete wall to insert fasteners for installation of approximately 1,500 square feet of insulation board and waterproofing membrane. Holes were ¼-inch in diameter and drilled to a depth of 3 inches. The drill was not equipped with dust collection.



7.1 µg


5 µg


0.071 mg


0.049 mg

August 2019

Densdeck® gypsum roof board installation #1769

Date: September 7-8, 2017

Location: Charlotte, NC


Project description: Four workers installed approximately 700 square feet of Densdeck® gypsum roof board using a motorized roof sawzall, drills, hand saw, and razor knife. Gypsum roof board debris was cleaned up using a leaf blower



4.9 µg

<4.4 µg

<4.4 µg

<4.5 µg


4.9 µg

<4.4 µg

<4.4 µg

<4.5 µg


0.10 mg

0.14 mg

<0.064 mg

0.30 mg


0.10 mg

0.14 mg

0.064 mg

0.30 mg

August 2019

Densdeck® gypsum roof board installation #1770


Location: Schaumburg, IL


Project description: Eight workers installed approximately 6,500 square feet of Densdeck® gypsum roof board with fasteners into a metal deck. Two of the eight workers also installed perimeter flashing by drilling into a concrete parapet wall using a hammer drill and fasteners.



<5.0 µg <5.0 µg

<5.0 µg <5.0 µg

<5.0 µg <5.0 µg

<5.0 µg <5.0 µg


5.3 µg 5.3 µg

5.3 µg 5.3 µg

5.3 µg 5.3 µg

5.3 µg 5.3 µg


<0.053 mg <0.053 mg

<0.053 mg <0.053 mg

<0.053 mg <0.053 mg

<0.053 mg <0.053 mg


0.053 mg 0.053 mg

0.053 mg 0.053 mg

0.053 mg 0.053 mg

0.053 mg 0.053 mg

August 2019

Roof ballast removal (shoveling and vacuuming) #1781


Location: Brooklyn Park, MN


Project description: Two workers removed approximately 8,000 square feet of roof ballast using shovels and a vacuum connected to a long suction tube that disposed the materials into the bed of a dump truck.



6.0 µg

8.2 µg


5.2 µg

7.1 µg


<0.06 mg

<0.06 mg


0.05 mg

0.05 mg

August 2019

Hot asphalt and gravel installation #1782


Location: Milwaukee, WI

Structure type: Public utility building

Project description: The project involved coating of an approximately 8,500 square foot roof surface with hot asphalt and dispersing gravel over the freshly applied hot asphalt. Equipment used for dispersing the gravel included a gravel spreader, shovels and brooms. Hot asphalt was spread with mops and asphalt wagons. 5 workers were performing tasks on the roof while two worked on the ground to load gravel from roll-off boxes to a gravel bucket that was lifted to the roof with a crane. One sampling pump failed so only 6 samples are reported below.



<6.7 µg

<6.7 µg

<6.7 µg

<7.1 µg

<7.0 µg

<6.8 µg


<5.3 µg

<5.3 µg

<5.3 µg

<5.6 µg

<5.6 µg

<5.4 µg


<0.067 mg

<0.067 mg

<0.067 mg

0.30 mg

August 2019

0.12 mg

0.13 mg


<0.053 mg

<0.053 mg

<0.053 mg

0.24 mg

0.096 mg

0.104 mg

August 2019

Hammer drilling into concrete deck for installation of roof board insulation #1790

Date: December 14, 2017

Location: South Bend, IN

Structure type: Hotel

Project description: Six workers installed approximately 1200 square feet of roof board insulation drilling into a concrete deck with a hammer drill that was not equipped with dust collection. Approximately 200 fasteners were installed to secure the insulation.


RCS in micrograms as an 8-hour TWA concentration:

<5.5 µg

<5.4 µg

<5.4 µg

<4.3 µg

<5.4 µg

<6.5 µg

Respirable dust in milligrams per cubic meter of air as an 8-hour TWA concentration:

0.054 mg

0.049 mg

0.042 mg

0.15 mg

0.043 mg

<0.065 mg

August 2019

Removal of concrete roof tiles #1795


Location: Diamond Bar, California


Project description: Five workers removed concrete roof tiles using hand removal methods and the following tools: hammers, nail pullers and push brooms.


RCS in micrograms as an 8-hour TWA concentration:

<5.0 µg

<12.0 µg

<9.0 µg

<5.0 µg

<20.0 µg

Respirable dust in milligrams per cubic meter of air as an 8-hour TWA concentration:

0.09 mg

0.10 mg

0.09 mg

0.10 mg

0.14 mg

August 2019

Perlite-based cover board removal #1801

Date: July 13, 2018

Location: Bradley, IL

Structure type: Public elementary school

Project description: The project involved manual and mechanical removal of the roofing membrane, perlite-based coverboard and polyiso insulation in a roof area of approximately 1,400 square feet. Safety data sheets for commercial perlite report various percentages of crystalline silica content according to the National Institutes of Health. The removal process involved cutting of the rubber roof membrane with utility knives and peeling back and removing the membrane to expose the cover board and insulation. A gas-powered roof cutter was used to cut through the perlite and insulation to produce smaller squares of material for ease of disposal. Manual tools were used to pry up the squares of cut material for transport to the chute at the edge of the roof. Eleven crew members were sampled but one sampling pump fell into the trash chute and broke.


Sample results for RCS in micrograms per cubic meter of air as an 8-hour TWA concentration:

<4.7 µg

<4.5 µg

<4.5 µg

<4.7 µg

<4.7 µg

<4.6 µg

<4.6 µg

<4.7 µg

<4.7 µg

<4.7 µg

Sample results for respirable dust in milligrams per cubic meter of air:

0.064 mg

0.22 mg

0.053 mg

0.14 mg

<0.047 mg

August 2019

0.061 mg

0.14 mg

0.054 mg

0.089 mg

0.081 mg

August 2019

Gravel-surface built-up roofing removal and installation project #1948

Date: June 26, 2019

Location: Park Ridge, IL

Structure type: Public high school building

Project description: Eight workers removed two large sections of a gravel-surfaced built up roofing system and the bulk sample of the removed material indicated a 10% concentration of quartz. Workers removed the built-up roof system with powered roof cutters, Sawzall and hand cutter in addition to using a leaf blower, rollers, roof spade, prybar, crowbar, razor knives, push broom, hammer, shovels and wheelbarrow. After clean-up, workers installed a two-ply layer of roofing felt in hot asphalt. Although 8 workers had personal breathing zone sampling equipment attached to each of them, only 7 readings are shown below since one sample was considered “not representative” because the sample inlet was moved away from the worker’s breathing zone by the worker during the work shift. .

Product installed: Johns Manville GlasPly IV and Trumbull Type III asphalt.


RCS as an 8-hour TWA concentration:

<4.6 µg/m3

<4.6 µg/m3

9.1 µg/m3

7.1 µg/m3

8.9 µg/m3

<4.7 µg/m3

17 µg/m3

Respirable dust as an 8-hour TWA:

0.30 mg/m3

0.15 mg/m3

0.25 mg/m3

0.12 mg/m3

1.2 mg/m3

0.11 mg/m3

1.1 mg/m3

objective data collection for roofing industry exposures ... · under 29 cfr §1926.1153(c), osha...

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