Permissible exposure limits are levels of exposures mandated by OSHA.
Occupational Safety and Health Administration (OSHA) is a regulatory part of the U.S. Department of Labor created to ensure safe and healthful working conditions for workers by setting and enforcing standards and by providing training, outreach, education and assistance.
It was created by Congress on 28 April 1971. It is headquartered in Washington, D.C., United States. Read more at osha.gov.