Resolving a thicket of issues raised by environmental litigators from several major firms, the First District Court of Appeal on Wednesday ruled that water providers regulated by the California Public Utilities Commission cannot be sued for injuries caused by chemicals in the water.

Resolving eight separate writ petitions and one appeal, the court unanimously concluded that while agencies regulated by the PUC are not subject to private actions, plaintiffs could take action against defendants not regulated by the commission.