Mont. Code Ann. § 39-51-3101

A person may not be excused from attending and testifying or from producing books, papers, correspondence, memoranda, and other records before the department or board, the presiding officer of an appeal tribunal, or any authorized representative of either of them or in obedience to the subpoena of the department or board or any member of the board or any authorized representative of the department in any cause or proceeding before the department or board 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. However, an individual may not 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 privilege against self-incrimination, to testify or produce evidence, documentary or otherwise, except that the individual testifying is not exempt from prosecution and punishment for perjury committed in testifying.