Petitioner seeks review of a final order of the Industrial Commission upholding the referee’s supplemental order denying petitioner disability benefits. We affirm.
Petitioner worked as a uranium miner from 1945 to 1960. From 1957 to 1960, his last three years as a miner, he was employed by Ben Zimmerman in Colorado. During the entire fifteen year period he worked as a miner he was exposed to silica dust, but his exposure to that dust ended in 1960, when he quit working as a miner.
In July 1972, petitioner was diagnosed as having silicosis. On March 2,1978, he filed a claim seeking compensation under the Colorado Occupational Disease Act, § 8-60-101 et seq., C.R.S.1973. The referee denied the claim, finding that the claimant had not developed the disease within five years of his last injurious exposure as required by § 8-60-110(l)(e), C.R.S.1973.1 On review, the Industrial Commission upheld the referee’s order.
I
Petitioner first contends that § 8-60-110(l)(e), C.R.S.1973, is arbitrary, unreasonable, and discriminatory and, thus, violates the equal protection clauses of the Fifth and Fourteenth Amendments. We disagree.
Initially, we note that we have jurisdiction to decide the constitutionality of statutes involving the Industrial Commission. See Matthews v. Industrial Commission, Colo.App., 627 P.2d 1123 (1980).
Section 8-60-110(1), C.R.S.1973, provides:
“An employer shall not be liable for compensation or other benefits under the provisions of this article for disability or death resulting from the diseases specified in section 8-60-109 unless the following conditions are shown to exist:
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“In the case of disability from silicosis, asbestosis, or anthracosis, the disablement [must have] resulted within five years from the date of the employee’s last injurious exposure to such disease while actually working for the employer against whom compensation is claimed ...”
As the right to disability benefits is not a fundamental right, and the class of disabled employees who have not developed silicosis within five years of their last injurious exposure is not a suspect class, the rational basis test must be applied. See Stevenson v. Industrial Commission, 190 Colo. 234, 545 P.2d 712 (1976). To pass judicial scrutiny under the rational basis test, the classification must bear a reasonable relationship to a legitimate state objective. Stevenson v. Industrial Commission, supra.
Although the time limitations contained in the statute have a harsh effect upon this claimant, the limitation operates in the same manner on all members of his class. Petitioner has not demonstrated any invidious discrimination as any time period, however lengthy, will have a harsh effect upon certain claimants. See Graber v. Peter Lametti Construction Co., 293 Minn. 465, 197 N.W.2d 443 (1972).
Furthermore, the General Assembly has a legitimate interest in preventing stale claims and evidently decided that proof after five years would become too speculative and unreliable. See Graber v. Peter Lamet-ti Construction Co., supra. The means it has chosen to effectuate this result, that of barring claims when disablement does not occur within five years of the last exposure, bears a reasonable relationship to that end. Graber v. Peter Lametti Construction Co., supra. Accordingly, § 8-60-110(l)(e), C.R. S.1973, is not unconstitutional.
II
Petitioner next contends that the five-year disablement requirement of § 8-60-110(l)(e), C.R.S.1973, operates as a statute of limitations rather than as a condition precedent to the stating of a claim for relief. Accordingly, petitioner argues that the employer and the insurer waived their right to assert the five year disablement requirement because they failed to assert it as an affirmative defense in the first hearing. We disagree.
The language of § 8-60-110(1), C.R. S.1973, makes disablement within five years a condition precedent to any liability of the employer. In establishing the five-year time limitation as a condition of liability, the General Assembly clearly indicated that § 8-60-110, C.R.S.1973, was to operate differently than § 8-60-111, C.R.S.1973, and, in the latter section, it imposed various time limitations upon the filing of claims. By separating the two sections and by clearly designating § 8-60-111, C.R.S.1973, as a statute of limitations, the General Assembly has shown a clear intent that if the conditions set forth in § 8-60-110, C.R.S.1973, are not fulfilled, the employee will not have any claim against his employer.
Section 8-60-110, C.R.S.1973, therefore, is jurisdictional in nature, rather than a statute of limitations, and thus, the parties’ failure to assert it at the first hearing will not operate as a waiver. See Ball v. Industrial Commission, 30 Colo.App. 583, 503 P.2d 1040 (1972).
Ill
Petitioner last contends that the repeal of § 8-60-110, C.R.S.1973, effective September 1975, removed the statute from consideration by the Commission. We disagree.
Absent an express legislative provision, the repeal of a statute will not operate retroactively to modify vested rights or liabilities. See § 2-4-303, C.R.S.1973; cf. Eight Thousand West Corp. v. Stewart, 37 Colo.App. 372, 546 P.2d 1281 (1976). Here, the parties’ rights and liabilities became fixed in 1965, when petitioner had not become disabled within five years after his last exposure to silica dust. As the General Assembly made no provision for retroactive application when it repealed the statute at issue, the repeal cannot operate retroactive*846ly to revitalize petitioner’s claim or to impair the employer’s right to rely upon the prior statute as a defense. See Brantley v. Phoenix Insurance Co., 536 S.W.2d 72 (Tex.Civ.App.1976).
Order affirmed.
STERNBERG, J., concurs. BERMAN, J., dissents.. Although the referee erroneously applied § 81-18-10(l)(g), C.R.S.1953, the law in effect at the time of the last injurious exposure, that error is without significance since the 1953 statute is identical to § 8-60-110(l)(e), C.R.S. 1973, the law in effect at the time disability occurred.