35 Pa. C.S. § 7339
All activities performed under the intrastate mutual aid system are deemed to be governmental functions. For the purposes of liability, all persons responding under the operational control of the requesting political subdivision shall be deemed to be employees of the requesting participating political subdivision. Except in cases of willful misconduct, gross negligence or bad faith, neither the participating political subdivisions nor their employees shall be liable for the death of or injury to persons or for damage to property when complying or attempting to comply with the system. This subchapter shall provide no immunity, rights or privileges for any individual responding to an incident where the response has not been requested by a participating political subdivision.
35 Pa.C.S. § 7339