San Diego Gas & Elec. Co. v. San Diego Reg'l Water Quality Control Bd.

*430 For many years, San Diego Gas & Electric Company (SDG&E) operated a power plant on the north side of San Diego Bay (Bay) and, in connection with its power plant operations, discharged waste into the Bay. The discharged waste consisted of various metals and toxic chemical compounds, which settled into the Bay's sediment and accumulated there along with similar waste discharged by unrelated shipyard companies. The accumulated pollutants adversely impact the beneficial uses of water, threatening aquatic life, aquatic-dependent wildlife, and human health.

After years of investigation, the government agency tasked with monitoring water quality, San Diego Regional Water Quality Control Board (Regional Board), issued a cleanup and abatement order (CAO) to SDG&E and several other entities. The Regional Board found that SDG&E caused *498 or permitted waste to be discharged into the Bay and thereby created, or threatened to create, pollution and nuisance conditions. ( Wat. Code, § 13304.)

SDG&E contested its designation as a responsible "person" under section 13304, subdivision (a). It claimed the Regional Board had not demonstrated, *431 by substantial evidence, that SDG&E's…