66 Pa.C.S. § 312: Privilege and immunity.

No person shall be excused from testifying or from producing any book, document, paper, or account in any investigation or inquiry by, or hearing before, the commission or its representative, when ordered to do so, upon the ground that the testimony or evidence, book, document, paper, or account required may tend to incriminate him or subject him to penalty or forfeiture. No person shall be prosecuted, punished, or subjected to any forfeiture or penalty for or on account of any act, transaction, matter, or thing concerning which he shall have been compelled, under objection, to testify or produce documentary evidence. No person so testifying shall be exempt from prosecution or punishment for any perjury committed by him in his testimony.