Criteria for a recommended standard

Alternate Titles

• Occupational exposure to hexavalent chromium
• Hexavalent chromium

Description

In this criteria document, the National Institute for Occupational Safety and Health (NIOSH) reviews the critical health effects studies of hexavalent chromium (Cr[VI]) compounds in order to update its assessment of the potential health effects of occupational exposure to Cr(VI) compounds and its recommendations to prevent and control these workplace exposures. NIOSH reviews the following aspects of workplace exposure to Cr(VI) compounds: the potential for exposures (Chapter 2), analytical methods and considerations (Chapter 3), human health effects (Chapter 4), experimental studies (Chapter 5), and quantitative risk assessments (Chapter 6). Based on evaluation of this information, NIOSH provides recommendations for a revised recommended exposure limit (REL) for Cr(VI) compounds (Chapter 7) and other recommendations for risk management (Chapter 8).^ This criteria document supersedes previous NIOSH Cr(VI) policy statements, including the 1975 NIOSH Criteria for a Recommended Standard: Occupational Exposure to Chromium(VI) and NIOSH Testimony to OSHA on the Proposed Rule on Occupational Exposure to Hexavalent Chromium [NIOSH 1975a, 2005a]. Key information in this document, including the NIOSH site visits and the NIOSH quantitative risk assessment, were previously submitted to the Occupational Safety and Health Administration (OSHA) and were publicly available during the OSHA Cr(VI) rule-making process. OSHA published its final standard for Cr(VI) compounds in 2006 [71 Fed. Reg. 10099 (2006)]. Cr(VI) compounds include a large group of chemicals with varying chemical properties, uses, and workplace exposures. Their properties include corrosion-resistance, durability, and hardness.^ Workers may be exposed to airborne Cr(VI) when these compounds are manufactured from other forms of Cr (e.g., the production of chromates from chromite ore); when products containing Cr(VI) are used to manufacture other products (e.g., chromate-containing paints, electroplating); or when products containing other forms of Cr are used in processes that result in the formation of Cr(VI) as a by-product (e.g., welding). In the marketplace, the most prevalent materials that contain chromium are chromite ore, chromium chemicals, ferroalloys, and metal. Sodium dichromate is the most common chromium chemical from which other Cr(VI) compounds may be produced. Cr(VI) compounds commonly manufactured include sodium dichromate, sodium chromate, potassium dichromate, potassium chromate, ammonium dichromate, and Cr(VI) oxide. Other manufactured materials containing Cr(VI) include various paint and primer pigments, graphic arts supplies, fungicides, and corrosion inhibitors.^ An estimated 558,000 U.S. workers are exposed to airborne Cr(VI) compounds in the workplace. Some of the industries in which the largest numbers of workers are exposed to high concentrations of airborne Cr(VI) compounds include electroplating, welding, and painting. An estimated 1,045,500 U.S. workers have dermal exposure to Cr(VI) in cement, primarily in the construction industry.

Subjects

Series Statement

• Criteria for a recommended standard