Cal. Veh. Code § 2531

In addition to taking action pursuant to Article 5 (commencing with Section 2540), the commissioner may deny, suspend, or revoke a license to transport hazardous material when it is evident that the applicant or licensee or his or her employees have repeatedly violated any provision of law to such an extent as to demonstrate that it would be unsafe and not in the public interest to permit the applicant or licensee to operate or permit the operation of any vehicle owned or controlled by him or her for the transportation of hazardous material upon the public highways.