Cal. LAB § 6362

The rights and duties set forth in this chapter apply to all employers who use hazardous substances in this state, to any person who sells a hazardous substance to any employer in this state, and to manufacturers who produce or sell hazardous substances in this state. The provisions of this chapter apply to hazardous substances which are present in the workplace as a result of workplace operations in such a manner that employees may be exposed under normal conditions of work or in a reasonably foreseeable emergency resulting from workplace operations. For purposes of this chapter, an emergency includes, but is not limited to, equipment failure, rupture of containers, or failure of control equipment, which may or do result in a release of a hazardous substance into the workplace.