For many chemicals, legal exposure limits carry high cancer risks

OSHA’s limits for known or likely human carcinogens almost always fall far short of protections the government seeks to give the general public. That’s according to an analysis by Adam M. Finkel — a former OSHA health regulatory divisions director now at the University of Pennsylvania — and the Center for Public Integrity.

The analysis estimates excess risk over time: If 1,000 workers are exposed to a chemical’s legal limit over their entire careers, how many will likely get cancer as a result? OSHA considers a 1-in-1,000 risk to be “clearly significant.” Below, compare estimated risks at OSHA limits to the risks at often-tighter “Threshold Limit Values” recommended by the American Conference of Governmental Industrial Hygienists, a nonprofit supported in part by industry. The method isn’t exact — no risk calculation is — but it shows how much hazards can vary under the law. (Details about how and where such chemicals are used, meanwhile, are partial rather than comprehensive because such information is limited.) Read about our methodology here.

Mouse over the graph to see examples of how these chemicals are used.

How many workers out of 1,000 would likely get cancer from career-long exposure to


Selected Industries

Silica, a substance for which OSHA has proposed tighter regulation, is not on the chart. OSHA has its own cancer-risk estimate for the current silica limit: up to 653 workers out of 1,000. The proposal, OSHA says, would reduce the risk to a maximum of 26 in 1,000.

Source: Analysis by former OSHA official Adam Finkel and the Center for Public Integrity using data from OSHA, the U.S. Environmental Protection Agency and the California EPA. Finkel and the Center relied on cancer-risk factors developed by the U.S. EPA and California’s EPA, a model also used by that state to estimate on-the-job risk. Read more about our methodology here.

Legal chemical-exposure limits often looser than recommended

Most of the Occupational Safety and Health Administration’s workplace exposure limits date to 1971, when the then-new agency adopted voluntary standards used by industry. But the nonprofit group that developed most of those guidelines, the American Conference of Governmental Industrial Hygienists, continued to update its work as chemical research mounted. Now its nonbinding recommendations, called Threshold Limit Values, are frequently more protective of workers than the government’s legal limits — one reason OSHA urges employers to follow voluntary standards instead.

Legal limits often looser than ACGIH voluntary limits

Source: Center for Public Integrity analysis of OSHA data.

Analysis includes chemicals with OSHA exposure limits and ACGIH recommended limits that can be compared.

A drop in the bucket

The federal government has workplace exposure limits for just a fraction of the chemicals to which workers are actually exposed. No one can say exactly how many chemicals are on the market, or even how many are widely used, but more than 84,000 have been registered with the U.S. Environmental Protection Agency under the Toxic Substances Control Act. The EPA, meanwhile, is permitted to disclose the names of only 2,238 chemicals made or used in the U.S. in quantities of 1 million pounds or more in 2011. (The rest were held back by companies under the mantle of confidential business information.)

= 100 chemicals
Among 84,000 listed chemicals,

470 have OSHA exposure limits.
2,238 high-use chemicals;

208 have OSHA exposure limits.

Source: Center for Public Integrity analysis of OSHA and EPA data.

No limits: Chemicals without workplace-exposure standards

Most chemicals in the workplace are unregulated in one key way: They don’t have federal exposure limits that set a legal standard for the amount workers can breathe each day. Here are a few examples of substances without Occupational Safety and Health Administration limits.

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widely used herbicide


The International Agency for Research on Cancer concluded in 2015 that glyphosate -- used in hundreds of products, including the weed killer Roundup -- is probably carcinogenic to humans.


Source: OSHA, National Institute for Occupational Safety and Health, International Agency for Research on Cancer, U.S. Environmental Protection Agency, California Department of Public Health.

Icons by Luis Prado, Wojciech Zasina, Leandro Mello Honda, yng, Cezary Rudaś, Olivier Guin, Christoffer Skogsmo, Yazmin Alanis, Ralf Schmitzer, and Sathish Selladurai from the Noun Project.