Welding Fumes Added to California’s Proposition 65 List
California’s Office of Environmental Health Hazard Assessment (OEHHA) has added welding fumes to its list of chemicals regulated under Proposition 65, a law intended to protect state residents from substances that cause cancer, birth defects, or reproductive harm. In its notice of intent to update the Proposition 65 list (PDF), OEHHA states that welding fumes meet the listing requirements due to the International Agency for Research on Cancer’s classification of welding fumes as a Group 1 carcinogen, IARC’s designation for agents that carry sufficient evidence of carcinogenicity in humans. The OEHHA notice explains that substances identified by IARC as human or animal carcinogens are required by California law to be listed as known carcinogens under Proposition 65. OEHHA received no feedback during the comment period, which was open from May 8, when the notice of intent was published, to June 8. The Proposition 65 listing of welding fumes became effective on July 17.
IARC’s assessment of welding fumes was published in 2018 in Volume 118 of the IARC Monographs, which identify and evaluate environmental factors that can increase carcinogenic risks to humans. The agency evaluated both welding fumes and UV radiation from welding as part of Volume 118. When IARC previously assessed the carcinogenicity of welding fumes in 1989, it classified them in Group 2B as “possibly carcinogenic to humans.” At that time, IARC based its classification on “limited evidence in human beings” and “inadequate evidence” in experimental animals. According to the agency, its updated classification for welding fumes is based on “substantial new evidence” from observational and experimental studies. UV radiation from welding is also classified by IARC as a Group 1 carcinogen.
Proposition 65 requires businesses to warn people in California about exposures to chemicals that can cause cancer in their products, homes, and workplaces or that are released into the environment. Under the law, California must publish and update at least yearly a list of covered chemicals. According to OEHHA, around 900 chemicals have been added to the Proposition 65 list since the law was passed as the Safe Drinking Water and Toxic Enforcement Act of 1986.
For more information about the welding fumes and Proposition 65, see OEHHA’s notice.
Related: Read “Source Reduction: Practical Issues in Minimizing Welding Fume Exposures” from the April 2017 issue of The Synergist.