(a) If, in response to a question posed, or a command to produce documents or other materials issued, by the Senate, the Assembly, or a committee, a witness asserts his or her privilege against self-incrimination, and the person presiding over the proceeding directs the witness that, notwithstanding that assertion of privilege, he or she is required to answer the question or produce the documents or other materials, the witness may not refuse to testify or produce the documents or other materials on the basis of his or her privilege against self-incrimination. However, if a witness is compelled to testify or produce documents or other materials notwithstanding his or her assertion of the privilege against self-incrimination, as described in this subdivision, both of the following shall apply:

1. (1) The witness may not be held to answer criminally or be subject criminally to any penalty or forfeiture for any fact or act touching upon either testimony that he or she was so compelled to provide, or documents or other materials that he or she was so compelled to produce.
2. (2) Any testimony or documents or other materials that the witness is so compelled to provide shall not be competent evidence in any criminal proceeding against the witness except in a prosecution for perjury or contempt.