California Code, Health and Safety Code - HSC § 43640

The state board may revoke, suspend, or restrict a certification of a previously certified device, or an exemption previously granted, upon a determination by the state board that the device no longer operates within the applicable criteria and standards adopted by the state board or no longer should be exempted.

Such a determination may be based on any relevant information, including, but not limited to, a change in the device, significant differences between certified and production models, or new data which bear upon the applicable certification criteria or standards and require the revocation of the device.