Opinion
RICHARDSON, J.Petitioner seeks review of an award by the Workers’ Compensation Appeals Board (the Board). We consider and resolve certain conflicts which have arisen over the appropriate method of determining the extent of an employer’s liability for an employee’s industrial injury resulting in permanent disability in those cases in which a portion of the over-all disability is attributable to a preexisting injury. In particular, we are here concerned with the interpretation and effect of amendments to Labor Code section 4658 which became effective April 1, 1972. (Unless otherwise indicated, all references are to the Labor Code.)
The facts are not disputed. While working for a number of employers over a 32-year period (1940-1972) petitioner sustained cumulative injury *4to his lungs resulting in an over-all permanent disability rating of 58 percent. One-half of this disability was found by the referee to be industrially related, one-quarter (25 percent) was the result of cigarette smoking, and the final one-quarter (25 percent) due to nonindustrial causes. Of the 25 percent attributable to cigarette smoking, one-third (8.33 percent of over-all disability) was found to have been incurred in the course of “on-the-job” smoking and is accordingly compensable. Thus, of the total 58 percent disability, approximately 33.75 percent (58 percent X 58.33 percent) was industrially related. The remaining 24.25 percent was attributable to other factors, and being nonindustrial in origin is not compensable. (§ 3600.) There is no disagreement among the parties as to the accuracy of these findings.
Under former law, the compensation due petitioner in such a case was easily calculated. Section 4658, as it read prior to April 1, 1972, provided that, for each percentage point of permanent disability which was of industrial origin, an injured worker was entitled to four weeks of compensation. (Stats. 1949, ch. 1583, p. 2833.) In petitioner’s situation, this would have meant an award of 135 weeks (4 X 33.75 percent). However, in 1971 the Legislature amended section 4658, establishing a different method for computing the number of weekly benefits to be awarded. Under the new statute, which is applicable to the instant case, the number of weekly benefits increases exponentially in proportion to the percentage of the disability. The following table of selected comparisons utilized by the Court of Appeal illustrates the effect of this change.
Percentage of worker’s permanent disability 10
24.25
33.75
40
50
58
70
80
90
Number of weekly benefits under § 4658, 1949-1972
40
97
135
160
200
236
280
320
360
Number of weekly benefits under § 4658 as effective 1972
30.25
91.75
143.25
180.75 241 297
381.25
461.25
541.25
Difficulties in applying the amended law have arisen in cases where, as here, only a portion of the overall disability has industrial origins. In *5such circumstances, the award is affected by the force of section 4750, which statute reads in full: “An employee who is suffering from a previous permanent disability or physical impairment and sustains permanent injury thereafter shall not receive from the employer compensation for the later injury in excess of the compensation allowed for such injury when considered by itself and not in conjunction with or in relation to the previous disability or impairment. [H] The employer shall not be liable for compensation to such an employee for the combined disability, but only for that portion due to the later injury as though no prior disability or impairment had existed.” The frequently expressed policy behind this section is that it will encourage employers to hire the handicapped.
The parties have suggested that in computing the number of weekly benefits to which petitioner is entitled under the new section 4658 there are three possible methods which may be utilized, described for the sake of convenience, as formulas A, B, and C. Under former section 4658 the compensation was the same regardless of which formula was applied. However, as a result of the 1971 amendments substantial differences ensue in the amount awarded a claimant depending on which formula is utilized.
Under formula A, adopted by the Board in petitioner’s case, there is subtracted from the total disability that portion which is nonindustrial, the remainder being the amount of compensable disability. Thus in the matter before us 24.25 percent, representing nonindustrial origin, is deducted from the 58 percent total disability with a net compensable disability of 33.75 percent. Under the schedule established by section 4658, subdivision (a), this entitled petitioner to 143.25 weekly benefits which may be converted in terms of dollars to an award of $10,027.50.
Formula B contemplates, first, determination of the number of statutory weekly benefits authorized under section 4658 for a 58 percent disability, namely, 297. This figure is then multiplied by the percentage of industrially related disability (58.33). The product is 173.25 weeks, which results in a total monetary award of $12,127.50.
Petitioner urges adoption of formula C, under which the 58 percent permanent disability is converted into its monetary equivalent of $20,790. From this figure is subtracted the dollar value ($6,422.50) of the 24.25 percent of the noncompensable, nonindustrial disability. The result is an award of $14,367.50, or the equivalent of 205.25 weekly benefits.
*6We have concluded that formula A is the proper one, and accordingly affirm the decision of the Board.
In our view this result is required by the express and unequivocal language of section 4750, supra. As we have previously noted, the purpose of that statute is to encourage employers to hire physically handicapped persons. The Legislature recognized that employers might refrain from engaging the services of the handicapped if,, upon subsequent injury, an employer was required to compensate the employee for an aggregate disability which included a previous injury. (Hegglin v. Workmen’s Comp. App. Bd. (1971) 4 Cal.3d 162, 173 [93 Cal.Rptr. 15, 480 P.2d 967]; State Compensation Ins. Fund v. Industrial Acc. Com. (Hutchinson) (1963) 59 Cal.2d 45, 49 [27 Cal.Rptr. 702, 377 P.2d 902].) In enacting section 4750, the Legislature has expressed a clear intent that the liability of one who employs a'previously disabled worker shall, in the event of a subsequent injury, be limited to that percentage of the over-all disability resulting from the later harm considered alone and as if it were the original injury. The principle has been expressed that “. . . [I]ndustry is to be charged only for those injuries arising out of and in the course of employment and only for the result of that particular injuiy when considered by itself and not in conjunction with or in relation to a previous injury.” (Gardner v. Industrial Acc. Com. (1938) 28 Cal.App.2d 682, 684 [83 P.2d 295].)
Bearing in "mind the beneficent public policy which prompted adoption of section 4750, as affirmed in Hegglin and Hutchinson, we conclude that only formula A results in an award complying with the provisions of section 4750. Petitioner has suffered a compensable disability of 33.75 percent. Under formula B, however, he would receive an award which, under the rates provided for in section 4658, subdivision (a), is equivalent to the amount given for a disability carrying a rating of approximately 39 percent. Application of formula C results in a recovery which is the same as that authorized by section 4658, subdivision (a), for a rating of 44 percent. This arithmetic leads to the inevitable conclusion that neither method B nor C can be reconciled with the mandate of section 4750 that the compensation for a subsequent injury be computed “as though no prior disability or impairment had existed.” On the contrary, B and C result in an enhancement of the benefits due to the existence of a preexisting physical impairment.
The application of either formula B or C would require us to discern an intent on the part of the Legislature that the 1971 amendments to *7section 4658 function so as to effect a repeal or at least a partial repeal of section 4750. Generally, we will not presume the existence of such an intent in the absence of an express declaration. (Ramos v. City of Santa Clara (1973) 35 Cal.App.3d 93, 97 [110 Cal.Rptr. 485].) Repeals by implication are not favored, and are recognized only when there is no rational basis for harmonizing two potentially conflicting laws. (In re White (1969) 1 Cal.3d 207, 212 [81 Cal.Rptr. 780, 460 P.2d 980].) Furthermore, we must assume that when passing a statute the Legislature is aware of existing related laws and intends to maintain a consistent body of rules. (Estate of Simpson (1954) 43 Cal.2d 594, 600 [275 P.2d 467, 47 A.L.R.2d 991]; American Friends Service Committee v. Procunier (1973) 33 Cal.App.3d 252 [109 Cal.Rptr. 22], hg. den.) In Theodor v. Superior Court (1972) 8 Cal.3d 77, 92 [104 Cal.Rptr. 226, 501 P.2d 234], we spoke “. . . of the policy that it should not ‘be presumed that the Legislature in the enactment of statutes intends to overthrow long-established principles of law unless such intention is made clearly to appear either by express declaration or by necessary implication.’ ”
Petitioner contends that there is an irreconcilable conflict between the legislative intent to increase workers’ compensation benefits as manifested by section 4658, on the one hand, and the limiting effect of section 4750 on the other. This conflict, it is argued, invokes the familiar rules of statutory construction requiring that we give effect to the more recently enacted law. (See City of Petaluma v. Pac. Tel. & Tel. Co. (1955) 44 Cal.2d 284, 288 [282 P.2d 43]; Rees v. Layton (1970) 6 Cal.App.3d 815, 821 [86 Cal.Rptr. 268].) Whenever possible, however, we must reconcile statutes and seek to avoid interpretations which would require us to ignore one statute or the other (see In re White, supra, 1 Cal.3d 207 at p. 212), and the rule giving precedence to the later statute is invoked only if the two cannot be harmonized. (Rees v. Layton, supra.) This is not such a case.
Section 4658 may be considered as a general provision establishing the amount of compensation benefits for a permanent disability, and section 4750 may be viewed as a specific rule limiting the benefits available in those cases where the employee has a preexisting permanent disability and thereafter sustains a further permanent injury. When so construed the statutes in question are complementary, not contradictory, and function together quite harmoniously, thus, serving the twin goals of providing proportionately greater benefits for more serious injuries while at the same time protecting employers from bearing a disproportionate share of a financial burden resulting from cumulative injuries. Even *8assuming, however, that a conflict exists, an equally familiar rule of statutory construction requires the more specific section 4750 to prevail over section 4658, the more general law applicable to the same subject (In re James M. (1973) 9 Cal.3d 517, 522 [108 Cal.Rptr. 89, 510 P.2d 33]; Simpson v. Cranston (1961) 56 Cal.2d 63, 69 [13 Cal.Rptr. 668, 362 P.2d 492]), and petitioner’s recovery must be limited in accord with the provisions of section 4750.
In urging the adoption of formula C, petitioner relies heavily on Labor Code section 3202, the so-called “liberality rule,” which reads: “The provisions of Division 4 and Division 5 of this code shall be liberally construed by the courts with the purpose of extending their benefits for the protection of persons injured in the course of their employment.” However, the policy underlying section 3202 cannot supplant the intent of the Legislature as expressed in a particular statute. (Ruiz v. Industrial Acc. Com. (1955) 45 Cal.2d 409, 413 [289 P.2d 229].) Where, as here, the relevant statutes may be reconciled, their provisions cannot be disregarded. This is so, as we said 40 years ago, even though the particular statutory language “is contrary to the basic policy of the statute.” (See Earl Ranch, Ltd. v. Industrial Acc. Com. (1935) 4 Cal.2d 767, 769 [53 P.2d 154].) The fact that the workers’ compensation laws are to be liberally construed “. . . does not mean that the legislative mandate of section 4750 is to be ignored.” (Wolski v. Industrial Acc. Com. (1945) 70 Cal.App.2d 427, 431-432 [161 P.2d 283].)
As petitioner correctly observes, under formula A adopted by the Board a worker who suffers a single injury resulting in, for example, a disability rating of 50 percent, will receive greater benefits than one who sustains two successive injuries each of which causes a permanent disability of 25 percent when considered alone. This result, however, is neither unjust nor unfair, petitioner’s arguments to the contrary notwithstanding. Rather, it is a consequence of the recent amendments to section 4658 and is consistent with the previously noted policy of encouraging employers to hire the disabled. There being no evidence to the contrary, this court must assume that such a result was contemplated by the Legislature.
By applying formula A we give effect, as we must to the express and unambiguous language of section 4750. It follows, accordingly, that the Board properly computed the benefits due petitioner and the award is affirmed.
Wright, C. J., McComb, J., Sullivan, J., and Clark, J., concurred.