airborne chemical exposure and osha compliance

Airborne Chemical

Exposure

A Review of Applicable OSHA

Standards, Monitoring Strategies,

and Potential Controls

32 millions workers work with and are potentially exposed

to one or more chemical hazards.OSHA Publication 3084

“Thousands of workers still are becoming ill and dying as

a result of exposure to hazardous chemicals.” –David

Michaels, Assistant Secretary of Labor, OSHA (2014)

OSHA has various standards to ensure workers are not

exposed to dangerous levels of hazardous chemicals at

the workplace.

Standards• 1910.1000 Air Contaminants

– 3 tables listing substances by name and corresponding exposure limits

• Z-1: Originally borrowed from 1968 ACGIH limits

• Z-2: Originally borrowed from existing 1970 ANSI limits

• Z-3: Mineral Dusts

• 1910.1001 to 1910.1052– Specific chemical standards (we will review an

example)

• Related: 1910.134– Respiratory protection

Time-Weighted Average• TWA

– The average concentration of a contaminant

to which an employee is exposed over a

period of time.

– OSHA Permissible Exposure Limits (PELs)

are based on 8-hour work days

– Measured in ppm or mg/m3

DEFINITIONS

TWA Example CalculationThe PEL for methyl alcohol is 200ppm

An employee is exposed to:

– 350ppm between 8AM and 12PM

– 0ppm between 12PM and 2:30PM

– 85ppm between 2:30PM and 4PM

What is TWA?

(350*4 hours)+(0*2.5 hours)+(85*1.5 hours)8 hours = ~191 ppm

Extended Work Shifts?

• OSHA only specifies 8-hour shifts in most

cases

• Brief and Scala Method is recommended:

Extended Work Shifts?What if you work a double shift? It is not simply

half the value for twice the time working.

RF = (8/16) * (24-16/16) = 0.25

The PEL for methyl alcohol is 200ppm (8 hours)

The 16-hour PEL for methyl alcohol is the

RF*200ppm = 50ppm

Mixture of

Contaminants?

Em=(C1÷L1)+(C2÷L2)+…(Cn÷Ln)

Where:

Em is the equivalent exposure for the mixture.

C is the concentration of a particular contaminant.

L is the exposure limit for that substance specified in subpart Z of 29 CFR part 1910.

The value of Em shall not exceed unity (1).

Example Calc.

Ceiling Values

• Denoted with (C) in Table Z-1

• Employee exposures “shall at no time

exceed the exposure limit given for that

substance.”

• If you can’t measure instantaneously, the

ceiling shall be assessed as a 15-minute

TWA.

Short Term

Exposure Limit• TWAs over 15-minute

periods (generally)

• Most are found in specific chemical standards

Action Level• Exposure concentrations

that trigger certain regulations (specific chemical standards)

DEFINITIONS

Exposure Assessment Programs

An effective exposure assessment program will:

1. Accurately characterize hazardous work

processes

2. Allow exposure data to be tracked over time

3. Demonstrate regulatory compliance

(documentation, analysis, schedule)

4. Prioritize controls used

Survey ProtocolPrior to conducting chemical sampling a survey protocol should be developed. This protocol serves as a guide in performing the survey. The amount of detail necessary will depend on the purpose of the survey and to whom the results will be submitted. At a minimum, the protocol should include the following:

1. Purpose of the survey. Why is the survey being conducted and what is the desired outcome? Background information such as previous surveys, operational or equipment changes should be referenced.

2. Where to sample. This identifies expected exposure sites. It is based on where chemicals are stored, transported, and used at the site, and what ventilation and airflow patterns exist.


3. What to sample. This is based on available information. What are the potential chemical hazards?

4. Who to sample. This is based on knowledge of the potential exposure sites and the various job requirements at the site. What job classifications or specific individuals should be considered for monitoring? Workers with the greatest potential for exposure must be included.


5. How many samples should be collected. Consider the number of exposure sites, job classifications, and potential chemical hazards. How many samples are necessary to assess the various exposure hazards?

6. How will the samples be collected and analyzed. After determining the potential hazards, what published methods are available, and which ones will provide the most meaningful data. Is there a potential for other chemical hazards in the area and should methods be considered which may provide screening information?

Risk Assessments

• Are any of the substances listed used in

work operations?

– Look at work processes in all areas

– Retrieve information from Safety Data Sheets

• Are they listed only in the Z tables, or is

there a specific chemical standard?

This is the employer’s responsibility!

Monitoring• Employee exposures must be determined

from breathing-zone air samples.

• Classify workers into SEGs (Similar Exposure Groups)

– Similar work operations at similar frequencies.

– Grouped by work title or department, but not necessarily

– Choose HIGHEST RISK operations at HIGHEST RISK times (worst-case).

Monitoring Equipment• Equipment needs vary greatly, depending

on the contaminant.

– In general, the contaminant is collected on a

filter over a known amount of time or air

volume.

– The filter is sent to a laboratory and the total

amount of contaminant is measured.

– The amount of contaminant is divided by the

total time or air volume.

• Contaminants such as solvents and

volatiles can often be collected with

passive monitors (e.g., charcoal or

dinitrophenylhydrazine)

Monitoring Equipment

• Other contaminants, such as dusts, metals, and

asbestos, are collected on glass fiber, mixed

cellulose ester, or PVC filters.


Monitoring Equipment• Personal Sampling Pumps –must be

calibrated accurately

• OSHA has an index of validated sampling and

analytical methods.

• It is best to consult with an industrial hygienist or directly with the analytical laboratory to determine the best sampling method.


Review of 1910.1025 - Lead

Scope• Does not apply to construction

industry or agricultural operations

(covered by other standards)

• Action Level defined as 30 ug/m3

for 8-hour TWA

• Includes metallic lead, inorganic

lead compounds, and organic lead

soaps—does not include all other

organic lead compounds

PEL

• 8-hour TWA = 50 ug/m3

• For shifts greater than 8 hours, use the

following formula:

– PEL = 400/hours worked in day


Initial Determination Lead Exposure

• Considerations:

– Info, observations, or calculations that indicate employee exposure to

lead

– Previous airborne measurements

– Employees report symptoms attributable to lead

• Initially, monitoring may be limited to a “representative sample

of the exposed employees who the employer reasonably

believes are exposed to the greatest airborne concentrations

of lead in the workplace.” (can be up to 12 months old)


Review of 1910.1025 - LeadResults are below the Action Level?

• Employer must create a written record of

determination.

• Must include considerations from previous slide

• Must include date, location within the worksite,

and the name and SS# of each employee

monitored.

Results are above the Action Level but below

PEL?

• Monitoring must be repeated every 6 months

until…

• Two consecutive measurements, taken at least 7

days apart, are below the Action Level.

• …then can be discontinued.



Results are above the PEL?

• Monitoring must be repeated every 3 months

until…

• Two consecutive measurements, taken at least 7

days apart, are below the PEL.

• …then monitoring must continue every 6 months

(previous slide).


Additional Monitoring

• If there is any production, process, control, or personnel

change that may result in new or additional lead

exposures, then monitoring must be conducted.

Notification and Written Compliance Program

• Employees must be notified of any monitoring results

within 15 days of receipt of results.

• A written compliance program must be developed

Limitations of PELs• “OSHA recognizes that many of its permissible

exposure limits (PELs) are outdated and

inadequate for ensuring protection of worker

health.”

– Adopted in 1970, from available consensus standards

at the time

– Almost 50 years of industrial experience, new

developments in technology, and scientific data since

then

NIOSH Recommended

Exposure Limits

• National Institute of Occupational Safety and

Health

– Under the Center for Disease Control

– Legislative mandate to recommend legally

enforceable standards to OSHA

– Evaluate all medical, biological, engineering,

chemical, and trade information

ACGIH Threshold Limit Values

• American Conference of Governmental

Industrial Hygienists

– Private, non-profit organization

– Health-based, not intended to be used as

legal standards

– “Gold standard”

OSHA vs. NIOSH vs. ACGIHFormaldehyde

OSHA

8-hour TWA 0.75 ppm

STEL 2 ppm

NIOSH

TWA 0.016 ppm (Ca)

Ceiling 0.1 ppm [15-minute]

ACGIH

Ceiling 0.3 ppm (URT, eye irr.)

Interpreting Results

Sample

• ppm = 180

• ug = 8200

• time = 392 minutes (6 hours 32 minutes)

• OSHA PEL for Xylene: 100ppm

-Is this an overexposure?

(Best case: ~146 ppm 8-hour TWA)

(180*6.5 + 0*1.5)/8)

Interpreting Results

Xylene Case Study - Next Steps?

• Employee interviews – tissue fixing in histology

department at a healthcare facility

– Was the work routine?

– Did anything happen out of the ordinary?

– How often do you perform this work?

– Are there other employees in your department that

also do this?

Controlling Employee Exposure

Xylene Case Study –

Mitigating Hazards• Elimination/Substitution

– Get rid of hazardous chemical in the first place

– Xylene substitute option: HistoClear Clearing Agent

(from safety data sheet)

• Engineering Controls

– Work was performed in a fume hood

– Can additional operations be performed under the hood? Does

this require changing the size of containers or other equipment?

– Is the fume hood functioning properly?

– Can general dilution ventilation be increased in the room?


Mitigating Hazards


Mitigating Hazards

• Administrative/Work Practice Controls

– Fume hood sash height O.K.?

– Re-training in proper chemical handling?

– Split shifts with another employee? I.e., if this

work is performed 6 hours a day, potentially

have 2 employees performing the work for 3

hours a day each.


Mitigating Hazards

• Personal Protective Equipment

– Air-purifying respirator is the last option

– All respiratory protection must comply with

1910.134, which includes medical clearance,

annual fit-testing, training, and equipment supply.

– APRs usually have an assigned protection factor

of 10

• If exposure is 180ppm with no respiratory protection,

then it can be estimated to be 18ppm with a respirator

with an APF of 10.

Controls

• The controls used to reduce lead exposure are laid out in detail in this standard:

– Mechanical ventilation testing must occur every 3 months

– If air is recirculated, a high efficiency filter must be used

– Job rotation schedule must include employee names, durations, and exposure levels

– Respirator use


Controls

• The controls used to reduce lead exposure are laid out in detail in this standard:– Employers must provide clean protective clothing

daily or weekly; launderer must be notified in writing and laundry must be labeled appropriately.

– Specific regulations on housekeeping, showering, lunchrooms, lavatories, etc.

– Medical surveillance program must be instituted for all employees exposed above the Action Level for more than 30 days a year.

• Included blood sampling


Do you have an exposure

monitoring plan?

QUESTIONS?

THANK YOU!

Mike Maffuccio, CIH

Environmental Compliance Consultant

Triumvirate Environmental

[email protected]

646-256-7396

mailto:[email protected]

airborne chemical exposure and osha compliance

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