Section 142D. The director of labor and workforce development and the commissioner of public health acting jointly may, by reasonable rules and regulations, exempt from the provisions of sections one hundred and forty-two A and one hundred and forty-two B, under such restrictions as they may deem advisable, (a) closed receptacles which are in the possession of the manufacturer by whom the contents of such receptacles were made or compounded or of a common carrier, provided in each case said director and commissioner are satisfied that such contents are to be used only outside the commonwealth; (b) receptacles containing material used exclusively as motor fuel; (c) receptacles containing material which, as last compounded, contained a per cent by weight of benzol, carbon tetrachloride or other substance which said director and commissioner determine to be not so hazardous to health as to warrant regulation.