California Code, Penal Code - PEN § 414a

No person, otherwise competent as a witness, is disqualified from testifying as such, concerning any offense under this act, on the ground that such testimony may incriminate himself, but no prosecution can afterwards be had against him for any offense concerning which he testified. The provisions of section 1111 of the Penal Code of this state are not applicable to any prosecutions brought under the provisions of this act.