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Compliance versus risk in assessing occupational exposures
R Tornero-Velez1, E Symanski, H Kromhout
1School of Public Health, University of North Carolina, Chapel Hill 27599-7400, USA.
Summary
Traditional compliance testing may underestimate worker health risks from chemical exposures. A new measure, probability of overexposure (theta), better reflects chronic health risks than compliance or exceedance probabilities.
Area of Science:
- Occupational Health
- Toxicology
- Risk Assessment
Background:
- Occupational exposure assessments often rely on compliance testing, measuring the probability of exceeding occupational exposure limits (OELs).
- Worker health risks, particularly chronic effects from long-term chemical exposure, depend on cumulative exposure, which is not directly assessed by compliance testing.
Purpose of the Study:
- To introduce and evaluate the probability of overexposure (theta) as a more relevant measure of individual health risk for chronic chemical exposures.
- To compare the utility of compliance (gamma) and overexposure (theta) probabilities in assessing occupational chemical risks.
Main Methods:
- A random-effects model was applied to data from 179 worker groups exposed to various chemical agents.
- Parameter estimates for mean exposure, and within- and between-worker variance components were calculated.
- These estimates were combined with OELs to derive probabilities of compliance (gamma) and overexposure (theta).
Main Results:
- Compliance testing can significantly underestimate health risks, especially with small sample sizes, as high compliance probabilities can coexist with substantial individual overexposure risks.
- The relationship between overexposure (theta) and exceedance (gamma) is influenced by variance components, meaning exceedance is not always a reliable surrogate for overexposure.
- Small sample sizes in compliance testing can lead to underestimation of actual health risks.
Conclusions:
- Current occupational exposure assessment practices focusing solely on compliance or exceedance are problematic for managing chronic health risks.
- Employers should prioritize evaluating chemical exposures based on the probability of overexposure (theta) to better protect worker health.
- The probability of overexposure (theta) offers a more accurate reflection of individual risk for chronic health effects compared to traditional compliance metrics.