California Code, Labor Code - LAB § 7862

(a) The employer shall inform contractors performing work on, or near, a process of the known potential fire, explosion, or toxic release hazards related to the contractor's work and the process, and require that contractors have trained their employees to a level adequate to safely perform their job. The employer shall also inform contractors of any applicable safety rules of the facility, and assure that the contractors have so informed their employees.

(b) The employer shall explain to contractors the applicable provisions of the emergency action plan required by Section 7868.

(c) Contractors shall assure that their employees have received training to safely perform their jobs and that these employees will adhere to all applicable work practices and safety rules of the facility.