No person shall be excused from attending and testifying or from producing books, papers, correspondence, memoranda and other records before the commissioner, an unemployment hearing officer, or any duly authorized representative of any of them, or in obedience to the subpoena of any of them in any cause or proceeding before the commissioner or an unemployment hearing officer, on the ground that the testimony or evidence, documentary or otherwise, required of the person may tend to incriminate the person or subject the person to a penalty or forfeiture; but no individual shall be prosecuted or subjected to any penalty or forfeiture for or on account of any transaction, matter or thing concerning which the individual is compelled after having claimed the individual's privilege against self-incrimination, to testify or produce evidence, documentary or otherwise, except that the individual so testifying shall not be exempt from prosecution and punishment for perjury committed in so testifying.