Baird

I. Introduction

In this case we hold that the California Environmental Quality Act (CEQA) (Pub. Resources Code, § 21000 et seq.) does not require an environmental impact report (EIR) for a project that might be affected by preexisting environmental conditions but will not change those conditions or otherwise have a significant effect on the environment.

Bi-Bett Corporation appeals from a judgment granting a writ of administrative mandate compelling Contra Costa County (the County) to set aside the approval of construction of a residential facility for treating young male drug and alcohol users. The action is being prosecuted by neighboring landowners who claim that the proposed facility is near areas that are contaminated by oil, mercury, wastewater and sewage. We reverse the judgment.

II. Facts and Procedure

Bi-Bett Corporation operates the Diablo Valley Ranch (the Ranch), an addiction treatment facility for 56 adult residents, under a conditional use permit in an area zoned for agricultural use. Bi-Bett wants to add a 20-bed facility for treatment of male adolescent drug and alcohol users. The County granted grading and building permits in 1991. Thereafter, a group…