Opinion
KEENAN, J.Dan River, Inc. appeals from a decision of the Industrial Commission finding that Anne M. Adkins is permanently disabled by irreversible, third-stage byssinosis. Dan River contends: (1) that Adkins’ claim is time-barred; (2) that the Commission’s appointment of an independent expert under Code § 65.1-90 violated the Commission’s own rules and deprived Dan River of due process; and (3) that no credible evidence supports the finding of byssinosis. We hold that Adkins’ claim is time-barred and reverse the Commission’s decision.
I.
Adkins worked in Dan River’s textile manufacturing establishment, with several interruptions in time, from the late 1920’s to 1976. She retired on May 28, 1976. Adkins filed a claim with the Commission on May 24, 1983. At the time of Adkins’ retirement, the worker’s compensation statute provided in pertinent part:
The right to compensation [for occupational disease] shall be forever barred unless a claim be filed with the Industrial Commission within three years for coal worker’s pneumoconiosis and two years for all other occupational diseases after a diagnosis of an occupational disease is first communicated to the employee or within five years from the date of the last injurious exposure in employment, whichever first occurs.
Code § 65.1-52 (1980 Repl. vol.). In 1982, the General Assembly amended this provision to read in pertinent part as follows:
The right to compensation [for occupational disease] shall be forever barred unless a claim be filed with the Industrial Commission within one of the following time periods:
* * * *
2. For byssinosis, two years after a diagnosis of the disease is first communicated to the employee or within seven years *323from the date of the last injurious exposure in employment, whichever first occurs.
1982 Va. Acts c. 82 (codified at Code § 65.1-52 (1980 Repl. vol. & Cum. Supp. 1986)).
The deputy commissioner adversely decided the merits of Adkins’ claim. In addition, the deputy commissioner concluded that although Adkins filed her claim within two years after a diagnosis was communicated to her, the claim was untimely because the five-year period in former Code § 65.1-52 expired on May 28, 1981, before the legislature extended the period to seven years.
A majority of the Commission found, as did the deputy commissioner, that Adkins received a diagnosis of byssinosis on May 17, 1983.1 Using the date of her retirement as the date of her “last injurious exposure” as provided by the statute, Owens v. Buchanan County Coal Co., 54 O.I.C. 299 (1972), the Commission found that Adkins had filed her claim within the seven-year period of the amended Code § 65.1-52. In holding that the seven-year period applied, the Commission stated:
[T]he law in effect at the time of the accident is controlling in this case, and . . . under § 65.1-49, the date of communication of occupational disease to the employee is the date of “happening of an injury by accident.” The Commission has so held in prior cases including Crenshaw v. Newport News Shipbuilding & Drydock Co., 57 OIC 83 (1977).
Thus, the Commission concluded that Adkins filed her claim within the time allowed from the date of her “accident,” seven years.
Chairman James, in a dissenting opinion, concluded that Adkins’ claim was barred when the five-year period in former Code § 65.1-52 expired. He stated that Dan River then acquired a “vested right” in the limitations bar and the General Assembly subsequently could not revive Adkins’ “dead claim.” As authority for this position, Chairman James cited, inter alia, Parris v. *324Appalachian Power Company (I.C. Claim No. 637-202). Dan River reiterates the “vested right” position of Chairman James’ dissenting opinion and urges us to find Parris dispositive of the issue.
II.
In order to determine whether Adkins’ claim was timely filed, we must decide whether to apply the limitation period of Code § 65.1-52 as it existed five years after the date of her last injurious exposure, or the limitation period in effect on the date that she first received communication of the diagnosis.
In deciding to apply the limitation period in effect on the date Adkins first received communication of a diagnosos of byssinosis, the Commission did not address the issue whether Dan River acquired a vested right in the five-year limitation period of former Code § 65.1-52. That limitations period was in effect on May 28, 1976, the date of Adkins’ last injurious exposure in employment. It remained in effect on May 28, 1981, five years later.
Former Code § 65.1-52 established a two-prong limitation covering byssinosis claims. Worded in the disjunctive, it provided that upon the occurrence of either event (two years after first communication of a diagnosis or five years from the date of last injurious exposure in employment), the employee’s right to compensation for an occupational disease was forever barred. Each prong described a distinct event, measured from a different point in time. The occurrence of one event immediately triggered the statutory bar. Once a claim was barred, the employer acquired a vested right. In Kesterson v. Hill, 101 Va. 739, 45 S.E. 288 (1903), the Supreme Court stated:
[I]t has been held that the right to set up the bar of a statute of limitations as a defense to a cause of action after the statute has run is a vested right, and cannot be taken away by legislation, either by a repeal of the statute without saving clause, or by an affirmative act; and that it is immaterial whether the action is for the recovery of real or personal property, or for the recovery of a money demand, or for the recovery of damages for a tort.
*325Id. at 743-44, 45 S.E. at 289; see also Hupman v. Cook, 640 F.2d 497 (4th Cir. 1981); Nicholas v. Lynchburg Training School & Hospital, 44 O.I.C. 198, 200 (1962).
After the oral argument in Adkins’ case, this Court affirmed the Commission’s decision in Parris v. Appalachian Power Co., 2 Va. App. 219, 343 S.E.2d 455 (1986), concluding that an employee who had not filed a claim within the five-year limitation period of former Code § 65.1-52 could not receive the benefit of the later amendment.2 The court held that the employer acquired a vested right in the running of the five-year limitation period. Id. at 228, 343 S.E.2d at 460.
In Parris, the date of the employee’s last injurious occupational exposure was October 22, 1975. In June 1981* he received a diagnosis of asbestosis. He filed his first claim in August 1981. In holding that the statute of limitations expired before Parris filed his claim, the court stated: “The running of the statute, standing alone, is a bar to subsequent claims. This is true even though the limitations period was subsequently amended.” 2 Va. App. at 229, 343 S.E.2d at 460.
The court in Parris also acknowledged: “We note, however, that an amendment to a period of limitation that enlarges the period is generally applicable to existing causes of action provided that an action already barred is not revived.” Id. at 229, 343 S.E.2d at 461.
We find the holding in Parris to be persuasive authority in the determination of Adkins’ claim. In applying the Kesterson analysis to a workers’ compensation claim, Parris recognized that once a single prong of the limitation period is fulfilled, the employee’s claim expires and the employer acquires a vested right in its expiration.
*326In Buenson Division Aeronca, Inc. v. McCauley, 221 Va. 430, 270 S.E.2d 734 (1980), the Supreme Court emphasized the significance of a vested right in determining what limitations period is applicable to a given claim. In Buenson, the employee sustained an injury in January 1977. At that time, Code § 65.1-99 placed a twelve month limitation period on the filing of an application for review based upon a change in condition. This twelve-month period was measured from the last day for which compensation was paid pursuant to an award. Code § 65.1-99 was amended, effective July 1977. The amendment enlarged the limitations period to twenty-four months. The employee filed an application for a change in condition nineteen months after the last day for which compensation was paid. The Commission held that amended Code § 65.1-99 applied and allowed the claim. The Supreme Court affirmed the Commission’s decision and stated: “Persuasive here is the fact that the new limitation period became effective before the old limitation would have barred McCauley’s claim.” 221 Va. at 434, 270 S.E.2d at 736. The court then distinguished that situation from a petition for appeal it refused in Biller v. ARA-Va. Skyline Co., 219 Va. liii (1978). In Biller, the employee was last paid compensation for June 28, 1976. On December 6, 1977, he filed an application for review based upon a change of condition. The Commission denied the application based on timeliness.3 The Supreme Court contrasted the facts of Biller with the facts before it in Buenson:
Unlike the situation here, however, Biller’s claim was barred by the old limitation before the enlarged restriction became effective. To have given retroactive effect to the amendment there would have resulted in the revival of a dead claim.
Buenson, 221 Va. at 434 n.2, 270 S.E.2d at 736 n.2. Applying this principle, we find that to allow Adkins’ claim based on amended Code § 65.1-52 would result in the revival of a dead claim.
*327In finding that Adkins’ claim had not expired, the Commission relied on Code § 65.1-49 and its holding in Crenshaw v. Newport News Shipbuilding & Drydock Co., 57 OIC 83 (1977). It reasoned that because § 65.1-49 assigns the date of first communication of the diagnosis of an occupational disease as the date of “happening of an injury by accident,” this became the “injury date” for purposes of determining which limitations period applies to Adkins’ claim.
Although Code § 65.1-49 was designed to place occupational diseases within the general structural and definitional framework of the Workers’ Compensation Act, we cannot find that it operates to fix the applicable limitations period where the specific statute setting forth the limitations period indicates a different legislative intent.
As stated above, both versions of Code § 65.1-52 establish a two-prong limitation period. One prong runs prospectively from the date of last injurious exposure in employment. The second prong runs prospectively from the date that the diagnosis of an occupational disease is first communicated. Thus, it is clear that the legislature intended that a different date fix the starting point of each of the two prongs. Both prongs contain an implicit recognition of the unique circumstances involved in making a claim for an occupational disease. In contrast, the purpose of Code § 65.1-49 is to place occupational diseases within the general operating framework of the Workers’ Compensation Act by creating a date of “injury.” Without this statutory link, parallel provisions dealing with occupational disease would have to be enacted that would merely duplicate existing provisions of the Act pertaining to injury by accident. Therefore, we conclude that the creation of an “injury” date in Code § 65.1-49 was not intended to limit or otherwise affect the unambiguous provisions of Code § 65.1-52. Those provisions contain fixed starting points and must be applied as they are plainly worded.
Adkins’ last injurious exposure in employment was May 28, 1976. At that time, former Code § 65.1-52 allowed her to file her claim either five years from this date or two years from May 16, 1983 (the date of first communication of a diagnosis of byssinosis), whichever occurred first. The five-year period expired first. This occurred on May 28, 1981. After that date, by operation of former Code § 65.1-52, Adkins’ claim was barred. The amend*328ment to § 65.1-52 did not take effect until July 1982. It could not operate to extend a claim that was barred. Parris, 2 Va. App. at 229, 343 S.E.2d at 460. To hold otherwise would negate the vested right which Dan River acquired on May 28, 1981, when the limitation period then in effect expired.
We recognize that our interpretation of Code § 65.1-52 may result in an individual losing a cause of action for an occupational disease before he is first told he has the disease. This potential for inequity, however, is inherent in the two-prong nature of the statute. To eliminate any inequity, legislative action would be required. The legislature, in its 1982 amendment to Code § 65.1-52, partially acknowledged this problem by extending one prong of the time limit in byssinosis cases from five to seven years. While this does not eliminate the above-stated problem, it does evince a legislative intent to address the problem from within Code § 65.1-52, rather than by application of Code § 65.1-49 or any other section of the Act.
We also note that in the special context created by the Workers’ Compensation Act, this problem cannot be resolved by a liberal construction of the statute. As stated by the Supreme Court in Winston v. City of Richmond, 196 Va. 403, 407-08, 83 S.E.2d 728, 731 (1954):
The right to compensation under the workmen’s compensation law is granted by statute, and in giving the right the legislature had full power to prescribe the time and manner of its exercise. When the legislature has spoken plainly it is not the function of courts to change or amend its enactments under the guise of construing them. The province of construction lies wholly within the domain of ambiguity, and that which is plain needs no interpretation.
The limitation period of Code § 65.1-52 is part of the substantive right of recovery created by the Act. Barksdale v. H.O. Engen, Inc., 218 Va. 496, 499, 237 S.E.2d 794, 796 (1977). Absent clear language to the contrary, this statute cannot be construed in derogation of another substantive right, namely, the vested right acquired by Dan River on May 29, 1981, when the five-year limitation period on Adkins’ cause of action expired. Ac*329cordingly, we find that the Commission erred in applying the seven-year limitation period of amended Code § 65.1-52, and that Adkins’ claim was time-barred after May 28, 1981, by the five-year limitation period in effect on that date.
Reversed and dismissed.
Cole, J., concurred.
The diagnosis was actually communicated to Adkins on May 16. Dan River contends that Adkins did not prove that the diagnosis was communicated to her on this date; however, Adkins testified that Dr. Hayes informed her of his diagnosis on the date of her examination, May 16, 1983.
In Parris, the employee’s claim alleged occupation-related asbestosis. He sought benefit of the 1983 amendment to Code § 65.1-52, Which removed the five-year limitation period for asbestosis and requires only the filing of a claim within two years after a diagnosis of asbestosis is first communicated to the employee. Prior to July 1, 1983, Code § 65.1-52 provided the same Imitations period for asbestosis as the pre-1982 language of that section allowed for byssinosis. Therefore, although Parris involved a different occupational disease, the statutory language interpreted by the court was the same as in the case before us.
We note that in Biller, the employee was not seeking compensation as a result of an occupational disease. Therefore, in determining which limitations period applied, the Supreme Court needed only to consider the date of injury in determining whether a vested right had accrued, based on the statute of limitations in effect on that date. The court was not required, as we are here, to apply the two-prong provision of former Code § 65.1-52 in determining whether a vested right had accrued.