Conn. Agencies Regs. § 29-349-182
The body of each such vehicle shall be fully enclosed. The doors shall be equipped with strong hinges securely bolted on the inside and provided with two suitable padlocks which shall be kept locked at all times when explosives are being carried. The underside of the body, together with the front end and sides of the body, shall be made fire-resistive by being covered with ¼ inch of sheet asbestos which, in turn shall be covered by 20 gauge galvanized iron or equivalent. The entire body, including the doors, should be so constructed that no bolt, screws, nails, or other metals shall be exposed on the inside thereof. Any exposed spark-producing metal on the inside of the body shall be covered with wood or other non-sparking material to prevent contact with packages of explosives.
Conn. Agencies Regs. § 29-349-182