Health-based exposure limits you can trust. Science-backed resources to advance worker protection.
Protecting worker health begins with setting clear, science-based exposure limits. The AIHA® Guideline Foundation’s Occupational Exposure Limit (OEL) Program supports OEHS professionals by developing and openly sharing health-based exposure limits for workplace chemicals.
Built on rigorous science and a transparent process, these values and supporting material help you evaluate exposures, assess risk and take action with confidence.
The OEL Program gives you free access to:
OEL Values: Set through methodologies and technical procedures that prioritize worker health above all other considerations and are publicly available for review.
Supporting Documentation: The technical justifications and risk characterization that accompany each OEL, providing visibility into the science behind the values.
Education: Opportunities to better understand how OELs are set, acquire new skills in applying them in work settings, and strengthen your risk assessment abilities.
Committee expertise, transparency, and legacy.
At the core of the OEL Program is a multidisciplinary, international committee composed of experts in occupational hygiene, toxicology, epidemiology, medicine, and risk assessment science.
Over 45 years ago, AIHA recognized a critical worker safety gap caused by a lack of clear exposure guidelines. To fill this need, the original committee was established. While the program operated under the auspices of the nonprofit Toxicology Excellence for Risk Assessment (TERA) starting in 2013, the expert members elected to return to AIHA management in October 2024.
Under the new designation of the AIHA OEL Committee, these industry-leading experts have implemented best-practice processes for setting health-based exposure limits. While the "WEEL" trademark was retained by TERA, the continuity of the committee members themselves ensures that the program’s methods and vital mission—establishing high-quality, health-based OELs for workplace exposures—remain strong and responsive to today’s emerging hazards. Learn more about the transition HERE.
Access the Occupational Exposure Limit (OEL) Table
This table provides a comprehensive list of Occupational Exposure Limits (OELs), detailing the maximum permissible concentrations for various chemical substances to ensure worker safety. It includes 8-Hour Time-Weighted Averages (TWA) for chronic exposure and Ceiling or Short-Term Limits to prevent acute health effects.
Advance the OEL Program through sponsorship.
Organizations and institutions can play a direct role in advancing worker health by participating in the OEL Program through sponsorship opportunities. External partners may propose chemicals for consideration, helping expand the library of OEL values and address emerging workplace risks.
Contact the AIHA Guideline Foundation today to learn more about sponsorship opportunities and how your organization can contribute to sustaining this essential program.
Support our work: Donate to the AIHA Guideline Foundation
The AIHA® Guideline Foundation OEL Program plays a crucial role in advancing worker protection, especially as resources for such initiatives become increasingly limited. Please consider a donation to the AIHA Guideline Foundation and sustain our vital work.
Make a contribution to the AIHA Guideline Foundation today. Donate Here
Last Updated On: 01/28/2026