On March 4, 2011, the California Office of Environmental Health Hazard Assessment (OEHHA) proposed to list four chemicals as known to the state to cause cancer under the Safe Drinking Water and Toxic Enforcement Act (Prop 65) based on the Labor Code mechanism contained in Health and Safety Code Section 25249.8(a). The four substances are: cyclopenta[cd]pyrene, ethanol in alcoholic beverages, leather dust and salted fish, Chinese-style.
Prop 65 was enacted in 1986 to protect citizens and the state's drinking water sources from chemicals known to cause cancer, birth defects or other reproductive harm, and to inform citizens about exposures to such chemicals. Prop 65 requires the governor to publish, at least annually, a list of such chemicals. Chemical product manufacturers, distributors and formulators have been challenged to label their products accordingly and make appropriate notifications, or determine the requirements do not apply because of safe harbor provisions. Historically, OEHHA has relied upon the authoritative body, qualified experts or formally required mechanisms to list chemicals.
In 2008, OEHHA requested comment on the utility of another listing mechanism, namely listing any substance identified by Labor Code sections 6382(b)(1) and 6382(d). That code references chemicals identified as carcinogens by the International Agency for Research on Cancer (IARC), while Labor Code section 6382(d) references chemicals listed pursuant to the federal Hazard Communications Standard (HCS), under regulations found at 29 C.F.R. section 1910.1200, which includes known and probable carcinogens identified by IARC, substances identified as known or probable carcinogens by the National Toxicology Program (NTP), and several other substances identified as carcinogens by the federal Occupational Safety and Health Act.
Industry strongly objected to using the Labor Code mechanism. They said the proposal would allow chemicals with no public input or OEHHA opportunity to comment on the underlying science of the listing, which is very different from the other listing mechanisms.
In 2009, the Alameda County Superior Court with OEHHA finding that Prop 65 imposed a 'clear ministerial duty' to list substances known to cause cancer or reproductive toxicity as identified by reference to the Labor Code. Appeals are ongoing.
The proposed listings are the first substances added under the Labor Code mechanism since June 12, 2009, when OEHHA added 30 chemicals. On March 4, 2011, OEHHA stated that three of the four substances proposed for listing (ethanol in alcoholic beverages, leather dust and salted fish, Chinese-style) have been identified by IARC as Group 1 (the agent is carcinogenic to humans) and the fourth substance proposed for listing (Cyclopenta[cd]pyrene) is identified by IARC as Group 2A (probably carcinogenic to humans).
In comments regarding its June 2009 proposed listings, concerns had been raised that OEHHA could propose to list chemicals under the Prop 65 Labor Code mechanism that have not been determined carcinogenic. Here's how: IARC identified a substance as Group 2B (possibly carcinogenic to humans), even though under that categorization IARC could designate a substance based on insufficient evidence of carcinogenicity in humans or experimental animals and that lack of evidentiary sufficiency would not support a listing decision via the authoritative body mechanism under Prop 65.
The availability and use of this listing mechanism sets a dangerous precedent. Because of the ease with which chemicals can be listed, this mechanism could easily become the mechanism of choice. It also seems premature to rely on this mechanism until the judicial appeal process has run its course.