Pennsylvania Statutes Title 77 P.S. Workers' Compensation § 481. Exclusiveness of remedy;  actions by and against third party;  contract indemnifying third party

(a) The liability of an employer under this act shall be exclusive and in place of any and all other liability to such employes,  1 his legal representative, husband or wife, parents, dependents, next of kin or anyone otherwise entitled to damages in any action at law or otherwise on account of any injury or death as defined in section 301(c)(1) and (2)   2 or occupational disease as defined in section 108.  3

(b) In the event injury or death to an employe is caused by a third party, then such employe, his legal representative, husband or wife, parents, dependents, next of kin, and anyone otherwise entitled to receive damages by reason thereof, may bring their action at law against such third party, but the employer, his insurance carrier, their servants and agents, employes, representatives acting on their behalf or at their request shall not be liable to a third party for damages, contribution, or indemnity in any action at law, or otherwise, unless liability for such damages, contributions or indemnity shall be expressly provided for in a written contract entered into by the party alleged to be liable prior to the date of the occurrence which gave rise to the action.