Gov. Code, § 20434

“Local firefighter” also means any officer or employee of a fire department of a contracting agency, except one whose principal duties are those of a telephone operator, clerk, stenographer, machinist, mechanic, or otherwise and whose functions do not clearly fall within the scope of active firefighting, fire prevention, fire training, hazardous materials, emergency medical services, or fire or arson investigation service, even though that employee is subject to occasional call, or is occasionally called upon, to perform duties within the scope of active firefighting, fire prevention, fire training, hazardous materials, emergency medical services, or fire or arson investigation service, but not excepting persons employed and qualifying as firefighters or equal or higher rank, irrespective of the duties to which they are assigned.

This section shall not apply to the employees of any contracting agency nor to any contracting agency until the agency elects to be subject to this section by amendment to its contract with the board, made pursuant to Section 20474 or by express provision in its contract with the board.