Using A Comprehensive Exposure
Assessment Strategy to Assess
Workplace Health Risks
Elizabeth L. Pullen, CIH
APOSHO 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
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
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Health Risk
Exposure
Very
High
High
Medium
Low
Toxicity
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
Exposure Assessment is the Core Activity
Hazardous Materials
Management and Procurement
Exposure Monitoring
Personal Protective Equipment
Medical Surveillance
Hearing Conservation
Education And Training
Engineering Controls
Hazard Communication
Compliance
Epidemiology
Exposure
Risk
Assessment
&
Management
(ERAM)
Work Practice Controls
Administrative Controls
Environmental
AIHA’s Exposure Risk
Assessment & Management Strategy
Start
Basic
Characterization
“A Strategy for
Assessing and
Managing
Occupational
Exposures”,
3rd edition
Exposure
Assessment
Acceptable
Exposure
Uncertain
Unacceptable
Exposure
Implement Controls
Further Information Gathering
Reassessment
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
AIHA’s Exposure Risk
Assessment & Management Strategy
Start
Basic
Characterization
“A Strategy for
Assessing and
Managing
Occupational
Exposures”,
3rd edition
Exposure
Assessment
Acceptable
Exposure
Uncertain
Unacceptable
Exposure
Implement Controls
Further Information Gathering
Reassessment
Basic Characterization
• Collect and organize information on
the
– Workplace
• Processes, equipment, controls
– Workforce
• Jobs, tasks, personnel, shiftwork
– Environmental Agents
• Chemical, physical, biological,
radiological
Exposure
Assessment
Establish Similar
Exposure Groups
Define Exposure
Profile
Select/Define
OELs
Compare:
Exposure Profile
and its
Uncertainty
Acceptable
Unacceptable
OEL
and its
Uncertainty
Uncertain
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
SEG
Environmental
Agents
Workplace
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
QUALITATIVE
DATA
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
3
50 – 100
Poorly
controlled
Controlled
2
10 – 50
1
<10
Well
controlled
Highly
controlled
Exposure Assessment
• Exposure assessment is a judgment
– Acceptable health risk
– Uncertain health risk
– Unacceptable health risk
SEG Exposure Control Category Follow-up
Exposure
Rating**
Recommended Follow Up
/ Exposure Control
0 (<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
** - Decision statistic = 95th percentile
Delivering Value
• Risk based prioritization and
management of IH programs
– Material substitution
– Engineering controls
– Work practice controls
– Personal protective equipment
– Medical surveillance
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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
Start
Basic
Characterization
Exposure
Assessment
Acceptable
Exposure
Note: Spreadsheets are good tools for
managing Basic Characterization and Initial
Exposure Assessments!
Uncertain
Unacceptable
Exposure
Control
Further Information Gathering
Reassessment
Continuous Improvement
• 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
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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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