Setting limits for safe exposure to toxic agents in the workplace is a complex process involving science, law, and policy. Development and use of occupational exposure limits (OELs) transcends national interests and international borders. Even though OELs have a lengthy history, and they form the cornerstone of most occupational risk assessment and risk management plans, their effectiveness in protecting worker health is increasingly being questioned. To better understand the current state of the OEL-setting process both in the United States and internationally, we need to understand what OELs are; how they are used in the workplace; how OELs are developed and why there are so many different OEL-setting entities; how often they are updated; whether. OELs are effective; and whether there are newer approaches which are more effective in protecting worker health than traditional ones that use OELs. Many in the workplace safety and health world would agree that OELs have served an important role in ensuring worker protection from toxic agent risks. However, the statutory and administrative methods for development and adoption of OELs may not be as effective as they were first envisioned when the OSH Act was adopted in 1970. The inefficient OEL-setting process in the United States, coupled with the changes occasioned by a more globally integrated U.S. economy, suggests that it may be time to review our current methods for assessing and managing risk in the occupational setting.