By James L. Curtis, Meagan Newman, and Craig B. Simonsen

The National Institute for Occupational Safety and Health has just issued a new recommended exposure limit (REL) for occupational exposure to hexavalent chromium compounds. The NIOSH Criteria for a Recommended Standard: Occupational Exposure to Hexavalent Chromium, Publication Number 2013-128 (January 2013), sets a significantly lower recommended exposure limit, that the Agency admits many industries will not be able to achieve.

The criteria document is derived from a NIOSH evaluation of critical health effects studies of occupational exposure to hexavalent chromium compounds. It provides recommendations for controlling workplace exposures including a revised recommended exposure limit derived “using current quantitative risk assessment methodology on human health effects data.”

NIOSH estimates that 558,000 U.S. workers are exposed to airborne hexavalent chromium compounds in the workplace. Impacted industries include electroplating, welding, and painting. In addition, over one million U.S. workers are estimated to have dermal exposure to hexavalent chromium compounds in cement, primarily in the construction industry.

Based on the results of the NIOSH quantitative risk assessment, NIOSH is now recommending that airborne exposure to all hexavalent chromium compounds be limited to a concentration of 0.2 μg/m3 for an 8-hr time-weighted average exposure, during a 40-hr work week. Note that NIOSH indicates that “some operations, including hard chromium electroplating, chromate-paint spray application, atomized-alloy spray-coating, and welding may have difficulty in consistently achieving exposures at or below the recommended exposure limit by means of engineering controls and work practices.” Also, “the extensive analysis of workplace exposures conducted for the OSHA rule-making process supports the NIOSH assessment that the REL is achievable in some workplaces but difficult to achieve in others.” 71 Fed. Reg. 10100 (February 28, 2006).