For the purpose of enforcing the provisions of this chapter, carriers engaged in intrastate commerce, and persons receiving drugs, devices, or cosmetics in intrastate commerce or holding such articles so received, shall, upon the request of the director, permit the director at reasonable times, to have access to and to copy all records showing the movement in intrastate commerce of any drug, device, or cosmetic, or the holding thereof during or after such movement, and the quantity, shipper, and consignee thereof; and it shall be unlawful for any such carrier or person to fail to permit such access to and the copying of any such records so requested when such request is accompanied by a statement in writing specifying the nature or kind of drug, device, or cosmetic to which such request relates: PROVIDED, That evidence obtained under this section shall not be used in a criminal prosecution of the person from whom obtained: PROVIDED FURTHER, That carriers shall not be subject to the other provisions of this chapter by reason of their receipt, carriage, holding, or delivery of drugs, devices, or cosmetics in the usual course of business as carriers.