NIOSH’s New Chemical Carcinogen Policy Adopts Lower Target Risk Level

By Ed Rutkowski

Washington State Convention Center, Seattle, Wash. (June 7, 2017)—Yesterday at AIHce EXP 2017, T.J. Lentz of NIOSH’s Document Development Branch explained the agency’s rationale for its new chemical carcinogen policy, which adopts a new target risk level for carcinogens at the lower 95 percent confidence limit on a concentration corresponding to 1 in 10,000 excess risk. The new target is ten times lower than the previous target of 1 in 1,000.

Lentz emphasized that the agency considers the new target to be a starting point for controls and that employers should try to ensure the lowest possible exposures to carcinogens.

The updated policy also introduces a new exposure value for carcinogens. The Risk Management Level for Carcinogens, or RML-CA, represents the daily maximum 8-hour time-weighted average concentration of a carcinogen above which workers should not be exposed. For chemicals where the 1-in-10,000 risk level is below the limit of quantitation (LOQ) of the relevant analytical method, the RML-CA will be set at the LOQ, Lentz said.

The agency has discontinued its longstanding practice of producing recommended exposure limits (RELs) for carcinogens. Lentz said that NIOSH is currently updating chemical-specific documents on its website to reflect the change from RELs to RML-CAs.

To identify carcinogenic substances, NIOSH will rely on existing classification schemes from the U.S. National Toxicology Program (NTP), the International Agency for Research on Cancer (IARC), and EPA. NTP classifies substances as either “known” or “reasonably suspected” to be carcinogenic. IARC and EPA both classify substances as carcinogenic, probably carcinogenic, or possibly carcinogenic. Chemicals classified in any of these categories will be considered carcinogens according to NIOSH’s new policy if the agency determines that the scientific basis for its classification has occupational relevance.

For possible carcinogens that have not been evaluated by NTP, IARC, or EPA but have occupational relevance, NIOSH will nominate the chemical for NTP evaluation. If NTP declines, NIOSH will consider conducting its own evaluation using the cancer classification criteria of the Globally Harmonized System for Classification and Labeling of Chemicals (GHS) that have been incorporated into OSHA’s hazard communication standard.

NIOSH anticipates developing risk management guidance for carcinogens that incorporates the industrial hygiene hierarchy of controls and Prevention through Design (PtD) concepts, Lentz said. PtD is the agency initiative that promotes “designing out” hazards from workplaces.

For more information, read Current Intelligence Bulletin 68: NIOSH Chemical Carcinogen Policy (PDF).

Ed Rutkowski is editor in chief of The Synergist. He can be reached at (703) 846-0734.

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