402 U.S. 558 (1971)
The United States filed an information charging that International Minerals & Chemical Corp. shipped sulfuric acid and hydrofluosilicic acid in interstate commerce. It did knowingly fail to show on the shipping papers the required classification of said property, to wit, Corrosive Liquid, in violation of 49 C.F.R. 173.427.1
Title 18 U.S.C. § 834(a) gave the Interstate Commerce Commission power to formulate regulations for the safe transportation of corrosive liquids.2 Section 834(f) stated that whoever knowingly violates any such regulation shall be fined or imprisoned.3 The regulatory agency promulgated a regulation requiring each shipper offering for transportation any hazardous material to describe that article on the shipping paper by the shipping name prescribed and by the classification prescribed.4
The District Court dismissed the information.5 The United States filed a notice of appeal to the Court of Appeals. In reliance on that section, it later moved to certify the case to this Court, which the Court of Appeals did. The Supreme Court noted probable jurisdiction.6
Whether knowledge of the regulation is also required in addition to knowledge of the shipment of dangerous materials to establish a knowing violation under 18 U.S.C. § 834(f)?7
The statute requires knowledge of the shipment of dangerous materials but does not require knowledge of the regulation itself.8 Ignorance of the law is no excuse.9 The word “regulations” is construed as a shorthand designation for specific acts or omissions which violate the Act.10 This does not create an exception to the general rule that ignorance of the law provides no defense.11
No. The information charged that International Minerals & Chemical Corp. shipped sulfuric acid and hydrofluosilicic acid in interstate commerce and did knowingly fail to show on the shipping papers the required classification of Corrosive Liquid. The statute and regulation require only that the shipper know it is shipping dangerous materials, not that it know the specific terms of 49 C.F.R. 173.427.12 The District Court dismissed the information on the basis of Boyce Motor Lines, Inc. v. United States, yet that precedent addressed only the vagueness of route-selection standards and did not require knowledge of the regulation.13 Legislative history confirms that Congress rejected strict liability while retaining the ordinary meaning of 'knowingly' without carving out an exception for ignorance of published regulations.14
Because sulfuric and hydrofluosilicic acid are dangerous or deleterious substances, anyone aware of shipping them is presumed to be aware of the 49 C.F.R. 173.427 regulation.15
Knowledge of the regulation is not required to establish a knowing violation under 18 U.S.C. § 834(f).16
Related opinions on this issue
Justice Stewart dissented because Congress made punishable only knowing violations of the regulation in question. That is what the law quite clearly says, what the federal courts have held, and what the legislative history confirms.17 He emphasized that prior decisions such as St. Johnsbury Trucking Co. v. United States and United States v. Chicago Express had interpreted the identical language to require knowledge of the regulation's terms.18 The legislative history of the 1960 amendments reinforced this reading. The Senate proposed language that would have eased the government's burden, but the House explicitly rejected it to retain the existing mens rea requirement and avoid creating almost absolute liability.19
Stewart concluded that the majority's construction effectively deletes the word 'knowingly' from the statute, contrary to both the enacted text and Congress's deliberate choice, and would expose even casual shippers to criminal liability for a single unknowing shipment.20