Using A Comprehensive Exposure Assessment Strategy to Assess Workplace Health Risks

Elizabeth L. Pullen, CIHAPOSHO 26 & Australasian

Safety Conference 2011

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What is Industrial Hygiene?

• Industrial hygiene is a process for managing the health risks associated with workplace exposures to chemical, physical, and biological agents

3

What is the process for managing workplace exposures?

• Assess and prioritize ALL exposures into “exposure control categories” to focus resources on highest risks.

• Differentiate “acceptable” from “unacceptable” exposures

• Control “unacceptable” exposures

Health Risk

VeryHigh

High

Medium

Low

Toxicity

Exposure

Comprehensive Strategy

• Why?– Exposures occur whether we’re there or not! – A comprehensive strategy best manages risk and

resources

• Comprehensive strategy – Directed at assessing all exposures for all workers on all

days– Transparent system provides foundation for feedback into

“Professional Judgment”.– Helps prevent occupational illnesses

Outcomes of Comprehensive Exposure Assessment & Management

• An assessment of the potential health risks faced by all workers

• Assurance that exposure controls are properly identified and utilized

• Demonstration of compliance with government and exposure guidelines

• The establishment of a historical record of exposure for all records

• Efficient and effective allocation of time and resources

Hazardous Materials Management and Procurement

Hearing Conservation

Engineering Controls

Administrative Controls

Work Practice Controls

Personal Protective Equipment

Medical Surveillance

Epidemiology

Hazard Communication

Education And Training

Exposure Monitoring

Environmental

Compliance

ExposureRisk

Assessment&

Management(ERAM)

Exposure Assessment is the Core Activity

Start

BasicCharacterization

Exposure Assessment

Uncertain

Implement Controls

Reassessment

Further Information Gathering

UnacceptableExposure

AcceptableExposure

AIHA’s Exposure Risk Assessment & Management Strategy

“A Strategy for Assessing and Managing Occupational Exposures”, 3rd edition

Exposure Assessment Strategy

• Reflects iterative “continuous improvement cycle” or real-world assessment programs

• Assessment include a combination of qualitative and quantitative information

Exposure Assessment

• The process of:

defining exposure profiles

and

judging the acceptability

of workplace exposures to environmental agents

Exposure Assessment Strategy – 7 Steps

1. Basic Characterization

2. Exposure Assessment– Define similar exposure groups

(SEGs)– Define the exposure profile– Judge acceptability of the profile for

each SEG

3. Further information gathering

Exposure Assessment Strategy

4. Control measures– Ventilation, Enclosures, PPE

5. Re-assessment

6. Communication and documentation

7. Implementation

Start

BasicCharacterization

Exposure Assessment

Uncertain

Implement Controls

Reassessment

Further Information Gathering

UnacceptableExposure

AcceptableExposure

AIHA’s Exposure Risk Assessment & Management Strategy

“A Strategy for Assessing and Managing Occupational Exposures”, 3rd edition

Basic Characterization

• Collect and organize information on the– Workplace

• Processes, equipment, controls

– Workforce• Jobs, tasks, personnel, shiftwork

– Environmental Agents• Chemical, physical, biological, radiological

Establish SimilarExposure Groups

Define ExposureProfile

Select/DefineOELs

Compare:

Exposure Profileand its

Uncertainty

OELand its

Uncertainty

Acceptable

UnacceptableUncertai

n

ExposureAssessment

Similar Exposure Group

• SEG – a group of employees having: – the same general exposure profile

because of the similarity and frequency of the tasks they perform,

– the similarity of the materials and processes with which they work,

– and the similarity in the way they perform the tasks.

SEG Concept

Workforce

WorkplaceEnvironmentalAgents

SEG

Establishing Exposure Limits

• Occupational Exposure Limits (OELs)– Different Sources

• Regulatory OEL• Authoritative OEL• Internal OEL• Working OEL

– Different Endpoints• Local, Systemic, Acute, Chronic

– Averaging Time• STEL, Ceiling, TWA, Excursion• Inhalation, Dermal (REACH DNEL)

Initial Exposure Rating Inputs

QUALITATIVEDATA

QUANTITATIVE

DATA

EXPOSURE ASSESSMENT

Initial Exposure Assessments

• May use worst-case assumption and then compare the overestimate to the OEL, which will account for the uncertainty

• May separate out ‘acceptable’ and ‘unacceptable’ exposures, to focus on ‘uncertain’ exposures

Exposure Rating (ER)

Rating % OEL Description

4 >100 Poorly controlled

3 50 – 100 Controlled

2 10 – 50 Well controlled

1 <10 Highly controlled

Exposure Assessment

• Exposure assessment is a judgment– Acceptable health risk– Uncertain health risk– Unacceptable health risk

SEG Exposure Control Category Follow-up

** - Decision statistic = 95th percentile

Exposure Rating**

Recommended Follow Up

/ Exposure Control0 (<1% of OEL) no action

1 (<10% of OEL) general HazCom

2 (10-50% of OEL) + chemical specific HazCom

3 (50-100% of OEL) + exposure surveillance, medical surveillance, work practices

4 (>100% of OEL) + respirators & engineering controls, work practice controls

5 (Multiples of OEL; e.g., based on respirator APFs)

+ immediate engineering controls or process shutdown, validate respirator selection

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Delivering Value

• Risk based prioritization and management of IH programs– Material substitution– Engineering controls– Work practice controls– Personal protective equipment– Medical surveillance

Exposure Assessments

• This is a cyclical process• Initial assessment is usually

based more on judgment and less on quantitative data

• It may have a higher degree of uncertainty

Note: Spreadsheets are good tools for managing Basic Characterization and Initial Exposure Assessments!

Start

BasicCharacterization

Exposure Assessment

Uncertain

Control

Reassessment

Further Information Gathering

UnacceptableExposure

AcceptableExposure

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• Make opportunities to verify and refine initial exposure assessments

• Each re-evaluation will build upon information collected and documented in past assessments

• We can’t do it all at once, so start the process and build on it

Continuous Improvement

Further Information

• References:

– “A Strategy for Assessing and Managing Occupational Exposures”, 3rd edition, AIHA Press

– AIHA Exposure Assessment Strategies Committee

– www.aiha.org

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