In USX Corporation v. Workers' Compensation Appeal Board (Rich), 727 A.2d 165 (Pa. Cmwlth. 1999), this Court interpreted Section 306(c)(8)(vi) of the Workers' Compensation Act: Because of the inclusion of the phrase 'at or prior to the time of employment,' in Section 306(c)(8)(vi) a more reasonable interpretation is that this provision simply dispenses with the 'last injurious exposure rule' that the last employer with which a claimant is employed and is cumulatively exposed to hazardous occupational noise is responsible for all work-related loss of hearing throughout the claimant's working life, not just for the hearing loss caused by his employment with that specific employer. In order for an employer not to be responsible for a hearing impairment under Section 306(c)(8)(vi), it must prove that the non-occupational cause of hearing loss . . . was present at or prior to the time of employment. Rich, 727 A.2d at 166-167.