Mateel Envtl. Justice Found. v. Office of Envtl. Health Hazard Assessment

*202 *223 INTRODUCTION

In 1989, the predecessor to respondent Office of Environmental Health Hazard Assessment (OEHHA), the lead agency charged with implementing California's Safe Drinking Water and Toxic Enforcement Act (Proposition 65) ( Health & Saf. Code, § 25249.5 et seq. ), adopted a regulation setting a "maximum allowable dose level" or MADL for lead as a reproductive toxicant. ( Cal. Code Regs., tit. 27, § 25805, subd. (b).) 1

In 2015, appellant Mateel Environmental Justice Foundation (Mateel) sued OEHHA, seeking a writ of mandate ( Code Civ. Proc., § 1085 ) and other relief to compel OEHHA to repeal that part of Regulations section 25805 setting a MADL for lead as a reproductive toxicant, seeking to invalidate the regulatory "safe harbor" level for lead of 0.5 microgram per day ("μg/day"). The trial court denied Mateel's motion for judgment on the pleadings for declaratory relief and/or writ of mandate and entered judgment in favor of OEHHA. 2 This timely appeal followed.

Mateel argues that OEHHA failed to comply with the Proposition 65 mandate that the MADL be based on an exposure having "no observable effect" when it utilized a "surrogate" "no observable effect…