Court Says Only Chemicals Known to Cause Cancer May Be Added to Prop. 65 List

A California appeals court has determined that the Office of Environmental Health Hazard Assessment (OEHHA) may not add styrene or vinyl acetate to the Proposition 65 (Prop. 65) list of chemicals known to the state to cause cancer because they have been identified as “possible” but not known carcinogens. Styrene Info. & Research Ctr. v. OEHHA, No. C064301 (Cal. Ct. App., 3d Dist., decided October 31, 2012). Styrene is used in food packaging.

The International Agency for Research on Cancer (IARC) had categorized
the substances as Group 2b chemicals, which are “possibly” carcinogenic
to humans, based on less than sufficient evidence of carcinogenicity in
experimental animals. The court acknowledged that the California Health
and Safety Code requires that the Prop. 65 list contain “at a minimum, the
substances identified by reference in Labor Code section 6382, subdivision
(d),” which addresses “hazardous substances” that extend “beyond those that
cause cancer or reproductive toxicity.” And it was on this basis that OEHHA
announced its intent to list the chemicals. Noting that this Labor Code
reference “must be read in conjunction with the prior language requiring the
Governor to publish a list of chemicals known to the state to cause cancer or
reproductive toxicity,” the court ruled that chemicals included in a 2b IARC
listing “may not qualify for Proposition 65 listing on that basis alone.”

The court expressly accorded OEHHA’s interpretation of Prop. 65 “little or no deference.” According to the court, OEHHA did not use the Labor Code method for listing chemicals in the first 15 years after Prop. 65’s enactment. “This has been OEHHA’s practice only during the last 10 years or so. ‘[A]n agency’s vacillating practice—i.e., adopting a new interpretation that contradicts a prior interpretation—is entitled to little or no weight.’ And OEHHA has not adopted any formal regulations to this effect.” The court also noted that administrative agencies may not “alter or amend” a statute or “enlarge or impair its scope.”

Thus the court concluded, “the Proposition 65 list is limited to chemicals for
which it has been determined, either by OEHHA through one of the methods
described in section 25249.8, subdivision (b), or through the Labor Code
method of adopting findings from authoritative sources, that the chemical
is known to cause cancer or reproductive toxicity.” Finding no other basis in
the record for listing the chemicals, the court affirmed a trial court decision
granting the trade group and chemical manufacturer’s motion for judgment
on the pleadings.