For the purpose of enforcing the provisions of sections 21a-335 to 21a-346, inclusive, carriers engaged in commerce and persons receiving hazardous substances in commerce or holding such hazardous substances so received shall, upon the request of an officer or employee duly designated by the administrator, permit such officer or employee, at reasonable times, to have access to and to copy all records showing the movement in commerce of any such hazardous substances, or the holding thereof during or after such movement, and the quantity, shipper and consignee thereof; and no such carrier or person shall fail to permit such access to and copying of any record so requested when such request is accompanied by a statement in writing specifying the nature or kind of such hazardous substance to which such request relates; provided evidence obtained under this section shall not be used in a criminal prosecution of the person from whom obtained and provided carriers shall not be subject to the other provisions of said sections by reason of their receipt, carriage, holding or delivery of hazardous substances in the usual course of business as carriers.