Gov. Code, § 31720.6

(a) If a safety member, a firefighter, or a member in active law enforcement who has completed five years or more of service under a pension system established pursuant to Chapter 4 (commencing with Section 31900) or under a pension system established pursuant to Chapter 5 (commencing with Section 32200) or both or under this retirement system or under the Public Employees’ Retirement System or under a retirement system established under this chapter in another county, and develops cancer, the cancer so developing or manifesting itself in those cases shall be presumed to arise out of and in the course of employment. The cancer so developing or manifesting itself in those cases shall in no case be attributed to any disease existing prior to that development or manifestation.

(b) Notwithstanding the existence of nonindustrial predisposing or contributing factors, any safety member, firefighter member, or member active in law enforcement described in subdivision (a) permanently incapacitated for the performance of duty as a result of cancer shall receive a service-connected disability retirement if the member demonstrates that he or she was exposed to a known carcinogen as a result of performance of job duties.

“Known carcinogen” for purposes of this section means those carcinogenic agents recognized by the International Agency for Research on Cancer, or the Director of the Department of Industrial Relations.

(c) The presumption is disputable and may be controverted by evidence, that the carcinogen to which the member has demonstrated exposure is not reasonably linked to the disabling cancer, provided that the primary site of the cancer has been established. Unless so controverted, the board is bound to find in accordance with the presumption. This presumption shall be extended to a member following termination of service for a period of three calendar months for each full year of the requisite service, but not to exceed 60 months in any circumstance, commencing with the last date actually worked in the specified capacity.

(d) “Firefighter,” for purposes of this section, includes a member engaged in active fire suppression who is not classified as a safety member.

(e) “Member in active law enforcement,” for purposes of this section, includes a member engaged in active law enforcement who is not classified as a safety member.