Subpoena power; immunity of natural persons required to

testify. The commission, or any member thereof, or the director of the division or his authorized representative, is hereby empowered to subpoena witnesses, to require their attendance and giving of testimony before it, and to require the production of books, papers and records in any proceeding before the commission or the division. No person shall be excused from attending and testifying or from producing books, papers and records before the commission or the division, or from obedience to the subpoena of the said commission or division, whether such subpoena be signed or issued by one or more of the members of the said commission, or the director of the division, in any hearing, investigation or proceeding held by or before the said commission or division or in any cause or proceeding in any court by or against the said commission or division, relative to matters within the jurisdiction of said commission or division, on the ground or for the reason that the testimony or evidence, documentary or otherwise, required of him may tend to incriminate him or subject him to a penalty or forfeiture; provided that nothing herein contained shall be construed as requiring any person to produce any books, papers or records, or to testify in response to any inquiry, not pertinent to some question lawfully before such commission or division or court for determination. No natural person shall be subjected to criminal prosecution, or to any penalty or forfeiture for or on account of any transaction, matter or thing concerning which he may be required to testify, or produce evidence, documentary or otherwise before said commission or division, or in obedience to its subpoena, or in any cause or proceeding, provided, that no person testifying shall be exempted from prosecution and punishment for perjury committed in so testifying.