A California court of appeal has ruled valid the methods by which the state updates the list of chemicals known to cause cancer or reproductive toxicity under the Safe Drinking Water and Toxic Enforcement Act (Prop. 65). Cal. Chamber of Commerce v. Brown, No. A125493 (Cal. Ct. App., decided June 6, 2011). Products containing these chemicals must be labeled with warnings to consumers.

The law requires the state to update the Prop. 65 list annually and authorizes Cal/EPA’s Office of Environmental Health Hazard Assessment (OEHHA) to add chemicals by one of three methods, including one specifically targeted in the lawsuit. The Chamber of Commerce challenged the method that requires adding to the list those chemicals identified under the Labor Code as causing cancer or reproductive toxicity. According to the Chamber, this method could be used to place chemicals on the initial list only. It sought a declaration to this effect and that “any future action . . . to automatically add Labor Code Chemicals to the Proposition 65 List as carcinogens or reproductive toxicants” exceeds OEHHA’s authority. Another issue the Chamber raised was whether the chemicals identified by reference to the Labor Code include chemicals on the list compiled by the American Conference of Government Industrial Hygienists (ACGIH).

The court concluded that the parties’ proposed statutory interpretations were both “semantically permissible” and thus that the law was ambiguous. Accordingly, the court referred to ballot summaries and arguments to determine voter intent in approving the Prop. 65 ballot measure. The court also looked to the law’s implementation history to determine that the Prop. 65 list is not frozen in time and can be expanded to add chemicals included under the Labor Code whether they are derived from lists compiled by the International Agency for Research on Cancer, National Toxicology Program or ACGIH.