California Code, Government Code - GOV § 31551

The persons expressly declared to be ineligible to membership by this article shall not become members of the retirement association, and, except as expressly excluded, the persons enumerated in this article or the California Public Employees' Pension Reform Act of 2013 shall become members of the association.

Persons employed as participants in a program of, and whose wages are paid in whole or in part by federal funds in accordance with, the Comprehensive Employment and Training Act of 1973 (Public Law 93-203)  1, as amended, are excluded from membership.  This exclusion shall not apply to active fire suppression personnel who are safety members pursuant to Sections 31469.3 and 31470.4.