The opinion of the court was delivered by: Justice Harrison
delivered the opinion of the court:
Claimant, Thomas Lefler, filed an application for adjustment of claim pursuant to the Workers' Occupational Diseases Act (Act) (Ill. Rev. Stat. 1981, ch. 48, par. 172.36 et seq.) alleging that he had contracted an occupational disease, coal worker's pneumoconiosis (black lung disease), arising out of and in the course of his employment with Freeman United Coal Mining Company (the employer). The arbitrator denied Lefler's claim, finding that Lefler had failed to prove that he had been exposed to coal dust, the hazard upon which his claim was based, or that coal dust exposure was causally related to the impairment he claimed.
The Industrial Commission affirmed the arbitrator's decision, with one commissioner Dissenting. On administrative review, the circuit court of Franklin County set aside the Commission's decision, holding that "the decision of the arbitrator was against the manifest evidence on the issue of exposure and disease." The court then remanded the cause to the Industrial Commission for reconsideration.
On remand, the Industrial Commission reversed the arbitrator's decision. It ruled that Lefler's condition was, in fact, causally related to an occupational disease arising out of and in the course of his employment and that he was permanently totally disabled. Accordingly, the Commission ordered the employer to pay Lefler $261.57 per week for life and awarded him other relief.
The circuit court subsequently confirmed the Commission's decision. Over the Dissent of two Justices, the Industrial Commission Division of the appellate court reversed. No. 5-97-0354WC (unpublished order under Supreme Court Rule 23). In its order, as modified on denial of rehearing, the court held that the Commission's initial decision denying Lefler's claim based on the arbitrator's findings regarding lack of exposure and causation was not against the manifest weight of the evidence and should not have been set aside. It therefore reversed the circuit court's judgment and reinstated the Commission's initial decision.
The two Dissenting appellate court Justices filed a statement that the case involves a substantial question which warrants consideration by our court. Lefler then petitioned us for leave to appeal. 177 Ill. 2d R. 315(a). We granted review. For the reasons that follow, we now reverse the judgment of the appellate court and remand the cause to the appellate court for further proceedings.
Before a reviewing court may overturn a decision of the Industrial Commission, it must find that the award was contrary to law or that the Commission's factual determinations were against the manifest weight of the evidence. Fitts v. Industrial Comm'n, 172 Ill. 2d 303, 307 (1996). It this case, the Industrial Commission's initial decision denying Lefler's claim was contrary to law, as the circuit court correctly determined.
As we have indicated, the Industrial Commission based its original determination on the decision of the arbitrator, who held that Lefler had adduced no evidence regarding the duration, extent or frequency of his exposure to coal dust and had failed to prove by a preponderance of the evidence that he was exposed to coal dust. Under the Workers' Occupational Diseases Act, however, Lefler was not required to present evidence regarding the amount, time and duration of his exposure to the hazards of an occupational disease. Section 1(d) of the Act expressly provides that an employee
"shall be conclusively deemed to have been exposed to the hazards of an occupational disease when, for any length of time however short, he or she is employed in an occupation or process in which the hazard of the disease exists ***." Ill. Rev. Stat. 1981, ch. 48, par. 172.36(d).
These conditions were satisfied here. There is no dispute that coal mining is an occupation in which the hazard of coal worker's pneumoconiosis is present. There is also no dispute that Lefler was employed as a coal miner. According to the record, Lefler worked as a coal miner for 33 years and was employed at a mine operated by Freeman United Coal Mining Company at the time he stopped working. Under these circumstances, the arbitrator should have taken Lefler's exposure to the hazard of coal worker's pneumoconiosis as having been conclusively established. Lefler was not obligated to present further evidence on the point, and it was not subject to challenge by the employer. See U.S. Industrial Chemical Co. v. Industrial Comm'n, 143 Ill. App. 3d 881, 890- 91 (1986).
In an effort to validate the arbitrator's decision, the employer argues that evidence as to the timing and extent of Lefler's exposure was properly considered because he was required to establish that he suffered medically significant exposure to coal dust on the final day of his employment. We disagree. The Act does specify that compensation is only payable where disablement "occurs within two years after the last day of the last exposure to the hazards of the disease," except in circumstances not relevant here. Ill. Rev. Stat. 1981, ch. 48, par. 172.36(f). In addition, where the disability was caused by coal worker's pneumoconiosis, the law provides that the application for compensation must be filed with the Commission within five years after the employee was last exposed where no compensation has been paid, or within five years after the last payment of compensation where such payments have been made. Ill. Rev. Stat. 1981, ch. 48, par. 172.41(c). Nothing in the Act, however, makes an employer's liability contingent on a claimant's ability to link his condition to exposure on the final day of his employment with that employer.
Claimants such as Lefler are apt to have been exposed to the hazards of coal worker's pneumoconiosis over a prolonged period of time in a variety of work settings. Under the Act, they are not required to establish which exposure led to their disease. They are not even required to identify the employer for whom they were working when they sustained the exposure that produced their disease. The employer who is liable is simply the "employer in whose employment the employee was last exposed to the hazard of the occupational disease claimed upon regardless of the length of time of such last exposure." Ill. Rev. Stat. 1981, ch. 48, par. 172.36(d). There is no dispute that the employer in this case met that description. Freeman United Coal Mining Company was "the employer in whose employment the employee was last exposed to the hazard of the occupational disease claimed" within the meaning of the Act. Accordingly, whether Lefler was actually exposed to coal dust on his last day of work and whether that exposure, if any, was medically significant, are not determinative of the employer's liability.
Thermos Co. v. Industrial Comm'n, 83 Ill. 2d 54 (1980), cited by the employer, does not mandate a contrary result. In that case it was necessary to determine "the date of the last exposure which caused the claimant's incapacity." Thermos Co., 83 Ill. 2d at 58. Such a determination, however, was not necessary in order to impose liability on the employer. It pertained to the wholly separate issues of when compensation should commence and which of the employer's multiple insurance carriers were required to pay ...