The California EPA comprises five departments and boards:
The Air Resources Board
ARB regulations can be found here, under Title 13 Division 3 and Title 17 Division 3.
The Department of Pesticide Regulation
DPR regulations can be found here.
The Department of Toxic Substances Control
DTSC regulations can be found here.
The Office of Environmental Health Hazard Assessment
OEHHA does not create or enforce regulations. OEHHA's mission is to protect and enhance public health and the environment by scientific evaluation of risks posed by hazardous substances. OEHHA produces a list of substances known to cause cancer or reproductive toxicity. This list can be found here.
The State Water Resources Control Board
SWRCB regulations can be found here.