In short, OSHA is a federal agency that regulates workplace safety, while the ACGIH is a scientific organization that studies occupational and environmental health issues. While the two are very different in structure and mandate, they have a relationship that is relevant for manufacturers.
OSHA, or the Occupational Safety and Health Administration, was signed into law by President Richard Nixon in 1970. The agency began work in 1971 with the mission to “assure safe and healthful working conditions for working men and women by setting and enforcing standards and by providing training, outreach, education and assistance.” Over the years, OSHA has added regulations to the legal code, most of which are contained in Standard 29 CFR Part 1910 Subpart Z. Many of these regulations set limits for worker exposure to various substances. These limits are often expressed as “permissible exposure limits,” or PEL’s. Workplaces must comply with these regulations or risk citations and fines.
OSHA oversees roughly seven million workplaces. The agency is organized under the Department of Labor and has ten regional offices, as well as area offices in most states. You can find OSHA’s frequently asked questions here.
The American Conference of Governmental Industrial Hygienists, or ACGIH, is a nonprofit organization established in 1938. Their motto is “Defining the Science of Occupational and Environmental Health.” Made up of a core of industrial hygiene workers, they collect and share information to support this goal. The organization also publishes the well-known reference work TLVs and BEIs. This annual guide for “evaluation and control of workplace exposures to chemical substances and physical agents” contains TLVs® (Threshold Limit Values, or exposure guidelines for over 700 chemical substances) and BEIs® (Biological Exposure Indices, or limits on over 80 more substances).
A TLV does not have any regulatory power in the workplace, but the number is still significant. It serves an advisory role to OSHA and to manufacturers who care about workplace safety. The ACGIH’s recommendations reflect the field’s latest research and expert analysis, so OSHA looks to it to inform its regulations. For example, if the ACGIH chooses to lower its limit for a particular substance, it is likely that OSHA will at least consider the issue. OSHA is under many conflicting pressures, so it is not an agency that acts quickly, but ACGIH recommendations are an influence on the agency. Some manufacturers who want to stay ahead of regulations and protect their workers according to the latest science follow ACGIH’s recommendations for exposure limits.