Conn. Agencies Regs. § 16-1-35
In the conduct of the hearing of a contested case any commissioner may act in behalf of the commissioners and summon and examine under oath such witnesses in relation to the affairs of any public service company as the commissioners may find advisable. Any commissioner may act in behalf of the commissioners to direct the production and examination of such books, records, vouchers, memoranda, documents, letters, contracts or other papers in relation to the affairs of any public service company as the commissioners may find advisable. The fees of witnesses summoned on behalf of the commissioners to appear before the commissioners or before any presiding officer in the hearing of a contested case, and the fees for summoning such witnesses shall be the same as in the superior court. All such fees, together with any other expenses authorized by statute whose method of payment is not otherwise provided shall be paid through the executive secretary of the Authority in the same manner as court expenses. In the event that any witness summoned under this authority objects to testifying or to producing any book or other paper ordered hereunder on the ground that such testimony, book or paper may tend to incriminate said witness, and in the further event that the commissioners or any commissioner directs said witness nevertheless to testify or to produce such book or paper and said witness complies or is compelled to comply by order of the court, then said witness shall not be prosecuted for any matter concerning which he has so testified, as provided in section 16-8 of the general statutes.
Conn. Agencies Regs. § 16-1-35