California Code, Insurance Code - INS § 676.8

(a) This section applies only to policies of workers' compensation insurance.

(b) After a policy is in effect, a notice of cancellation shall not be effective unless it complies with the notice requirements of this section and is based upon the occurrence, after the effective date of the policy, of one or more of the following:

(c) A policy shall not be canceled for the conditions specified in paragraph (1), (2), (5), or (6) of subdivision (b) except upon 10 days' written notice to the policyholder by the insurer.  A policy shall not be canceled for the conditions specified in paragraph (3) or (4) of subdivision (b) except upon 30 days' written notice to the policyholder by the insurer, provided that notice is not required if an insured and insurer consent to the cancellation and reissuance of a policy effective upon a material change in ownership or operations of the insured.  The time periods and procedures in subdivision (a) of Section 1013 of the Code of Civil Procedureshall be applicable if the notice is mailed.  If the policyholder remedies the condition to the insurer's satisfaction within the specified time period, the policy shall not be canceled by the insurer.

(d) Nothing in this section shall preclude, while policies are in force, changes in the premium rate required or authorized by law, regulation, or order of the commissioner, or otherwise agreed to between the policyholder and insurer.

(e) Any policy written for a term longer than one year, or any policy with no fixed expiration date, shall be considered as if written for successive policy periods of one year.