Cal. Health & Safety Code § 43821

In adopting criteria for the certification of fuel system evaporative loss control devices, the state board shall take into consideration the cost of the device and its installation, its durability, the ease and facility of determining whether the device, when installed on a motor vehicle, is properly functioning, and any other factors which, in the opinion of the state board, render such a device suitable or unsuitable for the control of motor vehicle air pollution or for the health, safety, and welfare of the public.