California Court of Appeal Requires That Only “Known” Carcinogens And Reproductive Toxins May Be Included On The Proposition 65 List

November 9, 2012


Last week a California court of appeal in Sacramento ruled that styrene and vinyl acetate could not be added to the list of chemicals subject to California’s Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986 (the “Act”). California’s Office of Environmental Health Hazard Assessment, OEHHA, had proposed to list the two chemicals based on a finding that they were “possibly” carcinogenic. The court found that only substances “known” to cause cancer or reproductive harm may be subject to Proposition 65’s requirements. The case is Styrene Information and Research Center v. Office of Environmental Health Hazard Assessment, 2012 Cal.App. LEXIS 1146 (Third Appellate District case no. C064301).

Proposition 65 prohibits the discharge of listed chemicals into drinking water under any circumstances, and prohibits exposing consumers to those chemicals without first giving a warning. Proposition 65 provides that private “bounty hunters” may file suit and share in stiff fines imposed on businesses that allegedly discharge listed chemicals into drinking water or fail to affix the required warning labels to their products.

Under the Act, chemicals may be included on the Proposition 65 list when they are “known to the state to cause cancer or reproductive toxicity.” The list is maintained by the Governor and must include, at a minimum, substances identified by California Labor Code section 6382(d). Labor Code section 6382(d), in turn, incorporates by reference substances on the federal Hazard Communication Standard, or HCS, 29 C.F.R. section 1910.1200. Among other sources, the HCS lists carcinogens based on the International Agency for Research on Cancer (“IARC”) Monographs. The HCS also identifies, however, chemicals that are not carcinogens or dangers to reproductive health.

Initially, the Governor’s list of Proposition 65 chemicals excluded chemicals that were found to be suspect carcinogens or reproductive toxins only in tests on animals. By 1989, however, a California court of appeal held that any chemical identified by reference in California Labor Code section 6382(d) as one that is known to cause cancer or reproductive harm in either humans or animals must be included on the Proposition 65 list. (AFL-CIO v. Deukmejian, 212 Cal.App.3d 425 (1989).) The Deukmejian case, however, did not directly address what it meant to be a “known” carcinogen or reproductive toxin.

In June 2009, OEHHA published a list of new chemicals to be added to the Proposition 65 list, including styrene and vinyl acetate. Styrene is used primarily to manufacture synthetic rubber and plastic for automobile and boat parts. It is also used to make carpet backing, plumbing, and electrical components. Vinyl acetate is a key ingredient for intermediates used in paints, adhesives, coatings, and acrylic fibers. The food industry uses vinyl acetate, for example, as a coating for plastic wraps and in food starch. OEHHA based its listing of these substances on 1995 and 2002 IARC monographs that categorized vinyl acetate and styrene, respectively, as suspect or “possibly carcinogenic.”

The Styrene Information and Research Center, or SIRC, filed its case against OEHHA a month later. SIRC, whose members include “95 percent of the North American styrene industry,” alleged that styrene was not a “known carcinogen” and was thus inappropriate for Proposition 65 listing. The trial court granted a temporary restraining order blocking the listing. Celanese Corporation then intervened, alleging that vinyl acetate was similarly not a known carcinogen, and should also be struck from the list. Celanese, a Delaware corporation based in Dallas, Texas, is the world’s leading manufacturer of vinyl acetate.

OEHHA admitted that the IARC categorized both styrene and vinyl acetate as merely “possibly carcinogenic,” but alleged its hands were tied by the requirement that all chemicals identified by Labor Code section 6382(d) and the HCS be included on the Proposition 65 list. The parties to the case filed motions for summary judgment. The trial court considered the motions and concluded that since styrene and vinyl acetate were not “known carcinogens,” they were not properly included on the Proposition 65 list. The trial court entered judgment for SIRC and Celanese, and OEHHA appealed.

OEHHA argued on appeal that under the prior Deukmejian case, even “possibly” carcinogenic substances could be incorporated from the HCS. The Court of Appeal disagreed. All the court had found in Deukmejian, it said, was “whether the Proposition 65 list must include both human and animal carcinogens.” It must. It did not address whether substances for which there was not sufficient evidence of carcinogenicity in either animals or humans should also be on the list. In its October 31 decision, the Court of Appeal went beyond Deukmejian and held that the Proposition 65 list should only incorporate substances from the HCS that are “known” carcinogens and reproductive toxins.

This finding is consistent with the purpose behind Proposition 65, the court concluded. The Ballot Pamphlet, for example, referred to “certain chemicals that are scientifically known -- not merely suspected, but known -- to cause cancer and birth defects.” The intent behind the statute was more important than OSHA’s and OEHHA’s interpretation of it. The HCS does not just list known carcinogens. It also lists “potential” carcinogens, a broader category of substances than was contemplated by Proposition 65. While that should not disqualify substances from the HCS or other federal lists from inclusion on the Proposition 65 list, they may only be included if there is otherwise “sufficient showing that they in fact cause cancer or reproductive toxicity.”

The IARC monograph finding styrene and vinyl acetate to be “possible carcinogens,” for which there may only be limited or insufficient evidence of human and animal carcinogenicity, was not a sufficient basis for including those substances on the list. OEHHA identified no other basis for including these chemicals. Therefore, they must be excluded. The Court of Appeal affirmed the trial court’s judgment, and neither styrene nor vinyl acetate will be placed on the Proposition 65 list for now.

Presumably these chemicals could be listed in the future should it later be demonstrated that they are known carcinogens. In the meantime, however, this court’s decision strips OEHHA of any authority to include “possible” carcinogens and reproductive toxins on the Proposition 65 list.

In the context of the IARC’s rating scheme, there must be “sufficient evidence of carcinogenicity” in animals and/or humans for a substance to qualify for Proposition 65. For all IARC “Group 1” substances, there was, by definition, “sufficient evidence of carcinogenicity in humans.” “Group 2A” substances, which are “probably” carcinogenic, may be imported onto the Proposition 65 list because that category necessarily includes substances for which there is “sufficient evidence of carcinogenicity” in animals. Substances that are merely “possibly” carcinogenic, on IARC’s “Group 2B” list, may not be included, since Group 2B includes substances for which there is, by definition, only limited or inadequate evidence of carcinogenicity in humans and animals. Styrene and vinyl acetate fell within Group 2B.

The Court’s decision in SIRC v. OSHA is of special significance because there are very few decisions from California courts of appeal regarding Proposition 65. This is presumably because so many Proposition 65 cases settle before reaching judgment. The decision provides comfort to manufacturers and retailers doing business in California that substances that are not actually “known” by the state to cause cancer or birth defects will not be subject to Proposition 65’s warning requirements and discharge prohibitions. It also offers a roadmap for businesses that monitor medical research in connection with formulation and engineering of new products. Finally, the decision presents opportunities to mount legal challenges to substances currently on the Proposition 65 list. IARC’s lists, however, are just one of several routes OEHHA may take to list a substance, and a substance’s known carcinogenicity or reproductive toxicity may be established elsewhere. Nevertheless, this decision offers a concrete standard for such challenges.

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