Occupational Exposure Limits—State of the Science
The process of developing and using occupational exposure limits is a cornerstone of industrial hygiene practice, with a history dating back to the 1880s. Occupational exposure limits, known as OELs, have not—until recently—evolved enough to reflect the advances in related sciences of toxicology, risk assessment, and exposure assessment.
Much of the pioneering effort to develop and promote OELs as a risk-management strategy occurred in the 1940s, when an organization now known as the American Conference of Governmental Industrial Hygienists created a list of occupational exposure limits for 132 specific chemicals. While these limits represented a significant step forward in the practice of occupational hygiene, they lacked consistent guidelines, explicit definitions, and technical documentation.
Gradually, these OELs and others have evolved to consider toxicological mechanisms of action, and uncertainties associated with the data available for assessing specific chemical hazards. Yet, there has still not been a concerted effort to explore how advances in toxicology, risk assessment, and exposure and risk management might better inform consistent and transparent processes for assessing chemical hazards and establishing OELs.
To begin to tackle these issues, researchers at the National Institute for Occupational Safety and Health worked with outside subject-matter experts. They developed a collection of 10 articles published in the Journal of Occupational and Environmental Hygiene focusing on the underlying principles for developing and interpreting OELs. The articles also discuss using and interpreting OELs in the context of evolving occupational risk assessment and management practices.