Understanding and adhering to occupational exposure limits (OELs) is critical to workplace safety and health management. These limits protect workers from harmful exposure to chemicals and other hazardous substances. Today, we’re focusing on the importance of OELs and how they play a crucial role in maintaining a safe work environment.
In this post, we’ll delve into occupational exposure limits, why they are essential, and how to implement them effectively in your workplace. By the end, you’ll have a comprehensive understanding of using OELs to safeguard employee health and ensure regulatory compliance.
What You’ll Learn
- Understanding OELs: Learn what occupational exposure limits are and their significance in protecting worker health.
- Importance of Compliance: Understand why adhering to OELs is crucial for regulatory compliance and maintaining a safe work environment.
- Implementing OELs: Discover practical steps for implementing and monitoring occupational exposure limits in your workplace to ensure ongoing safety.
Introduction
Occupational exposure limits are used to assess the risk of exposure. According to current knowledge, they are defined as airborne concentrations of individual chemical substances that should not harm or impair health or cause undue discomfort to nearly all workers. They are also understood to guard against narcosis or irritation, which could lead to industrial accidents.
A Global Picture of Occupational Exposure Limits
Most countries have adopted some form of occupational exposure limits, although how they are derived and used varies widely. This results in a confusing international landscape for identifying and applying such limits (Deveau et al., 2015; Lentz et al., 2016).
Various EHS technology solutions provide links to the multiple regulations and standards such as the ACGIH Threshold Limit Values (TLVs), NIOSH Recommended Exposure Limits (RELs), OSHA Permissible Exposure Limits (PELs), German MAK and BAT values, Safe Work Australia Workplace Exposure Standards (WESs) or UK EH40/2005 Workplace Exposure Standards (WELs), the IFA-GESTIS database brings together 33 lists from 28 countries (IFA, 2021) and is quite helpful.
The ACGIH Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) cover over 700 chemical substances, as well as details on carcinogenicity, particles, chemical mixtures, oxygen content, noise, radiation, lasers, ergonomics, cold stress, and heat stress. The NIOSH RELs are time-weighted average concentrations for up to a ten-hour work shift during a 40-hour working week. Short-term exposure limits are also designated. A ceiling REL is designated for certain substances and should not be exceeded at any time. OSHA has recommended PELs, which are time-weighted average concentrations that must not be exceeded during any eight-hour work shift of a 40-hour working week.
A Few Words about Occupational Exposure Limits
It is interesting to note that some exposure standards for the same substance can differ in different countries. The reasons for this can be different testing regimes, perceptions of risk, and influence by industry and stakeholders (Henry, 2021).
Although we accept that exposure to chemical substances must be kept ALARA (as low as reasonably achievable), industries may lobby regulatory authorities as they consider the practicability of achieving exposure below the exposure limit. This may also be why occupational exposure limits are not static but can increase or lower over time. As our substance knowledge changes, exposure limits may alter to reflect the risk.
Recently, some researchers have expressed concerns about the sufficiency of occupational exposure limits to protect individual worker health (Albin & Gustavsson, 2020).
Types of Occupational Exposure Limits
Occupational exposure limits are often reflected in three ways to reflect the duration of exposure. The typical exposure limit is expressed as a substance’s time-weighted average (TWA) concentration for an eight-hour working day and a five-day working week.
Provision is also made for short-term exposures above the TWA to some substances, as long as there is an equivalent excursion below the TWA. However, applying these short-term excursions (STEL) should be carefully reviewed to ensure the effects of acute exposure do not place workers at an increased risk of ill health.
The third occupational exposure limit is the peak limitation. This may be allocated to some substances where it is not appropriate to average the airborne concentration over an eight-hour shift because of the substance’s irritancy or fast effect on the body.
Summary
Occupational exposure limits do not differentiate between “safe” and “unsafe.” Still, they can be applied to assess the risk to exposed workers and assist in deciding on control measures to minimize exposure. Because each person may react differently if exposed to a substance, some people may show symptoms of ill health even if exposed to less than the occupational exposure limit. In other words, some workers may be more susceptible than others. The occupational exposure limits do not account for this individualism.
Similarly, occupational exposure limits have been developed on the assumption of a typical workday. However, given the changing nature of work (including production rate, use of substances, climatic conditions, and work intensity), applying occupational exposure standards should be used carefully.
Helpful Resources
- Occupational Health and Safety Management: A Practical Approach, by Charles Reese
- Fundamentals of Industrial Hygiene, by Barbara Plog
- Metals in the Workplace Blog Post, by Megan Tranter
Bibliography
Albin, M., & Gustavsson, P. (2020). A silent epidemic: occupational exposure limits are insufficiently protecting individual worker health. Scandinavian Journal of Work, Environment & Health, 46(1), 110-112. https://www.sjweh.fi/show_abstract.php?abstract_id=3864&fullText=1
Deveau, M., Chen, C.-P., Johanson, G., Krewski, D., Maier, A., Niven, K., Ripple, S., Schulte, P., Silk, j., Urbanus, J., Zalk, D., & Niemeier, R. (2015). The Global Landscape of Occupational Exposure Limits–Implementation of Harmonization Principles to Guide Limit Selection. Journal of Occupational and Environmental Hygiene, 12(1), 127-144. https://pubmed.ncbi.nlm.nih.gov/26099071/
Henry, E. (2021). Governing Occupational Exposure Using Thresholds: A Policy Biased Toward Industry. Science, Technology, & Human Values, May. https://doi.org/10.1177/01622439211015300
IFA. (2021). GESTIS International Limit Values. GESTIS – International Limits for Chemical Substances. https://limitvalue.ifa.dguv.de/
Lentz, T., Dotson, S., & Hornback, D. (2016, February 22). Occupational Exposure Limits – State of the Science. CDC Centers for Disease Control and Prevention. https://blogs.cdc.gov/niosh-science-blog/2016/02/22/oels/
