California Code, Labor Code - LAB § 6303

(a) “Place of employment” means any place, and the premises appurtenant thereto, where employment is carried on, except a place where the health and safety jurisdiction is vested by law in, and actively exercised by, any state or federal agency other than the division.

(b) “Employment” includes the carrying on of any trade, enterprise, project, industry, business, occupation, or work, including all excavation, demolition, and construction work, or any process or operation in any way related thereto, in which any person is engaged or permitted to work for hire, except household domestic service.

(c) “Employment,” for purposes of this division only, also includes volunteer firefighting when covered by Division 4 (commencing with Section 3200) pursuant to Section 3361.

(d) Subdivision (c) shall become operative on January 1, 2004.