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Using A Comprehensive Exposure Assessment Strategy to Assess Workplace Health Risks
Elizabeth L. Pullen, CIHAPOSHO 26 & Australasian
Safety Conference 2011
1
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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