On Dec. 23, 2021, eight substances were added to the Report on Carcinogens, bringing the total list to 256 substances that are known, or reasonably anticipated, to cause cancer in humans.

This was the 15th Report on Carcinogens, which is a cumulative report, mandated by Congress and prepared by the National Toxicology Program for the Secretary of the U.S. Department of Health and Human Services.