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NIOSH Chemical Carcinogen Policy

December 2016
DHHS (NIOSH) Publication Number 2017-100

	Cover tumbnail for NIOSH Chemical Carcinogen Policy, document 2017-100

Occupational exposure to chemical carcinogens still presents risks to many in the workforce. The burden from exposure to occupational carcinogens on workers, their families, employers, and the nation is difficult to measure. Cases are missed and go unreported because of the length of time, often decades, between exposure to a carcinogen and resultant cancer and because cancers can also have non-occupational causes, making it difficult to determine causation in individual cases. To aid in the prevention of occupational cancer, the National Institute for Occupational Safety and Health (NIOSH) develops guidance to protect workers from adverse effects of occupational carcinogens. This effort has spanned more than 40 years. In this current document, the policy by which NIOSH classifies chemicals as carcinogens, identifies control levels, and addresses analytical feasibility is being updated because of advances in science and with the intent of providing transparent guidance on how NIOSH assesses and addresses cancer risks.

Underlying this policy is the recognition that there is no known safe level of exposure to a carcinogen, and therefore that reduction of worker exposure to chemical carcinogens as much as possible through elimination or substitution and engineering controls is the primary way to prevent occupational cancer. Accordingly, this policy no longer uses the term recommended exposure limit (REL) for chemical carcinogens; rather NIOSH will only recommend an initial starting point for control, called the Risk Management Limit for Carcinogens (RML-CA). For each chemical identified as a carcinogen, this level corresponds to the 95% lower confidence limit of the risk estimate of one excess cancer case in 10,000 workers in a 45-year working lifetime. Keeping exposures within the risk level of 1 in 10,000 is the minimum level of protection and striving for lower levels of exposure is recommended. When measurement of the occupational carcinogen at the RML-CA is not analytically feasible at the 1 in 10,000 risk estimate, NIOSH will set the RML-CA at the limit of quantification (LOQ) of the analytical method. In addition, NIOSH will continue to evaluate available information on existing engineering controls and also make that information available when publishing the RML-CA.

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