Cal. Labor Code § 143

(a) Any employer may apply to the board for a permanent variance from an occupational safety and health standard, order, special order, or portion thereof, upon a showing of an alternate program, method, practice, means, device, or process which will provide equal or superior safety for employees. (b) The board shall issue such variance if it determines on the record, after opportunity for an investigation where appropriate and a hearing, that the proponent of the variance has demonstrated by a preponderance of the evidence that the conditions, practices, means, methods, operations, or processes used or proposed to be used by an employer will provide employment and places of employment to his employees which are as safe and healthful as those which would prevail if he complied with the standard. The variance so issued shall prescribe the conditions the employer must maintain, and the practices, means, methods, operations, and processes which he must adopt and utilize to the extent they differ from the standard in question. (c) The board is authorized to grant a variance from any standard or portion thereof whenever it determines such variance is necessary to permit an employer to participate in an experiment approved by the director designed to demonstrate or validate new and improved techniques to safeguard the health or safety of workers. (d) A permanent variance may be modified or revoked upon application by an employer, employees, or the division, or by the board on its own motion, in the manner prescribed for its issuance under this section at any time.