California Code, Government Code - GOV § 31720.9

(a) If a peace officer member, as defined in Sections 830.1 to 830.5, inclusive, of the Penal Code, or firefighter member, with 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, under the Public Employees' Retirement System, or under a retirement system established under this chapter in another county, becomes ill or dies due to exposure to a biochemical substance, the illness that develops or manifests itself in those cases shall be presumed to arise out of, and in the course of, employment. The illness that develops or manifests itself in those cases shall in no case be attributed to any illness existing prior to that development or manifestation.

(b) Any peace officer member or firefighter member, as described in subdivision (a), who becomes permanently incapacitated as a result of exposure to a biochemical substance shall receive a service-connected disability retirement.

(c) The presumption described in subdivision (a) is rebuttable by other evidence. Unless rebutted, 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) For purposes of this section, a peace officer member or firefighter member, as described in subdivision (a), does not include a member whose principal duties are clerical or otherwise do not clearly fall within the scope of active law enforcement services or active firefighting services, such as stenographers, telephone operators, and other office workers.

(e) “Biochemical substance” means any biological or chemical agent that may be used as a weapon of mass destruction, including, but not limited to, any chemical warfare agent, weaponized biological agent, or nuclear or radiological agent, as these terms are defined in Section 11417 of the Penal Code.