Currrent as of February 4, 2022

Labor Code § 5500.5

Employer liability for occupational disease or cumulative injury; Apportionment

(a) Except as otherwise provided in Section 5500.6, liability for occupational disease or cumulative injury claims filed or asserted on or after January 1, 1978, shall be limited to those employers who employed the employee during a period of four years immediately preceding either the date of injury, as determined pursuant to Section 5412, or the last date on which the employee was employed in an occupation exposing him or her to the hazards of the occupational disease or cumulative injury, whichever occurs first. Commencing January 1, 1979, and thereafter on the first day of January for each of the next two years, the liability period for occupational disease or cumulative injury shall be decreased by one year so that liability is limited in the following manner:
For claims filed or
asserted on or after: The period shall be:
January 1, 1979 three years
January 1, 1980 two years
January 1, 1981 and thereafter one year
In the event that none of the employers during the above referenced periods of occupational disease or cumulative injury are insured for workers’ compensation coverage or an approved alternative thereof, liability shall be imposed upon the last year of employment exposing the employee to the hazards of the occupational disease or cumulative injury for which an employer is insured for workers’ compensation coverage or an approved alternative thereof.
Any employer held liable for workers’ compensation benefits as a result of another employer’s failure to secure the payment of compensation as required by this division shall be entitled to reimbursement from the employers who were unlawfully uninsured during the last year of the employee’s employment, and shall be subrogated to the rights granted to the employee against the unlawfully uninsured employers under the provisions of Article 1 (commencing with Section 3700) of Chapter 4 of Part 1 of Division 4.
If, based upon all the evidence presented, the appeals board or workers’ compensation judge finds the existence of cumulative injury or occupational disease, liability for the cumulative injury or occupational disease shall not be apportioned to prior or subsequent years; however, in determining the liability, evidence of disability due to specific injury, disability due to nonindustrial causes, or disability previously compensated for by way of a findings and award or order approving compromise and release, or a voluntary payment of disability, may be admissible for purposes of apportionment.

(b) Where a claim for compensation benefits is made on account of an occupational disease or cumulative injury which may have arisen out of more than one employment, the application shall state the names and addresses of all employers liable under subdivision (a), the places of employment, and the approximate periods of employment where the employee was exposed to the hazards of the occupational disease or cumulative injury. If the application is not so prepared or omits necessary and proper employers, any interested party, at or prior to the first hearing, may request the appeals board to join as defendant any necessary or proper party. If the request is made prior to the first hearing on the application, the appeals board shall forthwith join the employer as a party defendant and cause a copy of the application together with a notice of the time and place of hearing to be served upon the omitted employer; provided, the notice can be given within the time specified in this division. If the notice cannot be timely given or if the motion for joinder is made at the time of the first hearing, then the appeals board or the workers’ compensation judge before whom the hearing is held, if it is found that the omitted employer named is a necessary or proper party, may order a joinder of the party and continue the hearing so that proper notice may be given to the party or parties so joined. Only one continuance shall be allowed for the purpose of joining additional parties. Subsequent to the first hearing the appeals board shall join as a party defendant any additional employer when it appears that the employer is a proper party, but the liability of the employer shall not be determined until supplemental proceedings are instituted.

(c) In any case involving a claim of occupational disease or cumulative injury occurring as a result of more than one employment within the appropriate time period set forth in subdivision (a), the employee making the claim, or his or her dependents, may elect to proceed against any one or more of the employers. Where such an election is made, the employee must successfully prove his or her claim against any one of the employers named, and any award which the appeals board shall issue awarding compensation benefits shall be a joint and several award as against any two or more employers who may be held liable for compensation benefits. If, during the pendency of any claim wherein the employee or his or her dependents has made an election to proceed against one or more employers, it should appear that there is another proper party not yet joined, the additional party shall be joined as a defendant by the appeals board on the motion of any party in interest, but the liability of the employer shall not be determined until supplemental proceedings are instituted. Any employer joined as a defendant subsequent to the first hearing or subsequent to the election provided herein shall not be entitled to participate in any of the proceedings prior to the appeal board’s final decision, nor to any continuance or further proceedings, but may be permitted to ascertain from the employee or his or her dependents such information as will enable the employer to determine the time, place, and duration of the alleged employment. On supplemental proceedings, however, the right of the employer to full and complete examination or cross–examination shall not be restricted.


(1) In the event a self–insured employer which owns and operates a work location in the State of California, sells or has sold the ownership and operation of the work location pursuant to a sale of a business or all or part of the assets of a business to another self–insured person or entity after January 1, 1974, but before January 1, 1978, and all the requirements of subparagraphs (A) to (D), inclusive, exist, then the liability of the employer–seller and employer–buyer, respectively, for cumulative injuries suffered by employees employed at the work location immediately before the sale shall, until January 1, 1986, be governed by the provisions of this section which were in effect on the date of that sale.

(A) The sale constitutes a material change in ownership of such work location.
(B) The person or entity making the purchase continues the operation of the work location.
(C) The person or entity becomes the employer of substantially all of the employees of the employer–seller.
(D) The agreement of sale makes no special provision for the allocation of liabilities for workers’ compensation between the buyer and the seller.

(2) For purposes of this subdivision:

(A) “Work location” shall mean any fixed place of business, office, or plant where employees regularly work in the trade or business of the employer.

(B) A “material change in ownership” shall mean a change in ownership whereby the employer–seller does not retain, directly or indirectly, through one or more corporate entities, associations, trusts, partnerships, joint ventures, or family members, a controlling interest in the work location.

(3) This subdivision shall have no force or effect on or after January 1, 1986, unless otherwise extended by the Legislature prior to that date, and it shall not have any force or effect as respects an employee who, subsequent to the sale described in paragraph (1) and prior to the date of his or her application for compensation benefits has been filed, is transferred to a different work location by the employer–buyer.

(4) If any provision of this subdivision or the application thereof to any person or circumstances is held invalid, that invalidity shall not affect other provisions or applications of this subdivision which can be given effect without the invalid provision or application, and to this end the provisions of this subdivision are severable.

(e) At any time within one year after the appeals board has made an award for compensation benefits in connection with an occupational disease or cumulative injury, any employer held liable under the award may institute proceedings before the appeals board for the purpose of determining an apportionment of liability or right of contribution. The proceeding shall not diminish, restrict, or alter in any way the recovery previously allowed the employee or his or her dependents, but shall be limited to a determination of the respective contribution rights, interest or liabilities of all the employers joined in the proceeding, either initially or supplementally; provided, however, if the appeals board finds on supplemental proceedings for the purpose of determining an apportionment of liability or of a right of contribution that an employer previously held liable in fact has no liability, it may dismiss the employer and amend its original award in such manner as may be required.

(f) If any proceeding before the appeals board for the purpose of determining an apportionment of liability or of a right of contribution where any employee incurred a disability or death resulting from silicosis in underground metal mining operations, the determination of the respective rights and interests of all of the employers joined in the proceedings either initially or supplementally shall be as follows:

(1) All employers whose underground metal mining operations resulted in a silicotic exposure during the period of the employee’s employment in those operations shall be jointly and severally liable for the payment of compensation and of medical, surgical, legal and hospital expense which may be awarded to the employee or his or her estate or dependents as the result of disability or death resulting from or aggravated by the exposure.

(2) In making its determination in the supplemental proceeding for the purpose of determining an apportionment of liability or of a right of contribution of percentage liabilities of the various employers engaged in underground metal mining operations the appeals board shall consider as a rebuttal presumption that employment in underground work in any mine for a continuous period of more than three calendar months will result in a silicotic exposure for the employee so employed during the period of employment if the underground metal mine was driven or sunk in rock having a composition which will result in dissemination of silica or silicotic dust particles when drilled, blasted, or transported.

(g) Any employer shall be entitled to rebut the presumption by showing to the satisfaction of the appeals board, or the workers’ compensation judge, that the mining methods used by the employer in the employee’s place of employment did not result during his or her employment in the creation of silica dust in sufficient amount or concentration to constitute a silicotic hazard. Dust counts, competently made, at intervals and in locations as meet the requirements of the Division of Occupational Safety and Health for safe working conditions may be received as evidence of the amount and concentration of silica dust in the workings where the counts have been made at the time when they were made. The appeals board may from time to time, as its experience may indicate proper, promulgate orders as to the frequency with which dust counts shall be taken in different types of workings in order to justify their acceptance as evidence of the existence or nonexistence of a silicotic hazard in the property where they have been taken.

(h) The amendments to this section adopted at the 1959 Regular Session of the Legislature shall operate retroactively, and shall apply retrospectively to any cases pending before the appeals board or courts. From and after the date this section becomes effective no payment shall be made out of the fund used for payment of the additional compensation provided for in Section 4751, or out of any other state funds, in satisfaction of any liability heretofore incurred or hereafter incurred, except awards which have become final without regard to the continuing jurisdiction of the appeals board on that effective date, and the state and its funds shall be without liability therefor. This subdivision shall not in any way effect a reduction in any benefit conferred or which may be conferred upon any injured employee or his dependents.

(i) The amendments to this section adopted at the 1977 Regular Session of the Legislature shall apply to any claims for benefits under this division which are filed or asserted on or after January 1, 1978, unless otherwise specified in this section.


Added Stats 1977 ch 17 § 29, effective March 25, 1977. Amended Stats 1977 ch 360 § 1; Stats 1980 ch 676 § 232; Stats 1985 ch 326 § 20.

Labor Code 5500.5