California Code, Public Resources Code - PRC § 4259

(a) The use or possession of fireworks is prohibited within any hazardous fire area designated pursuant to Section 4252 or 4258. However, the use of fireworks within any hazardous fire area may be allowed, if the use is determined by the director not to present a fire hazard.

(b) Notwithstanding subdivision (a), fireworks may be possessed in a vehicle on any public highway traversing a hazardous fire area when not otherwise prohibited.