19 CFR § 12.41 - Prohibited films.
(a) Importers of films, shall certify on Customs Form 3291 that the imported films contain no obscene or immoral matter, nor any matter advocating or urging treason or insurrection against the United States or forcible resistance to any law of the United States, nor any threat to take the life or inflict bodily harm upon any person in the United States. When imported films are claimed to be free of duty as American goods returned, this certification may be made on Customs Form 3311, or its electronic equivalent, in the space designated “Remarks” in lieu of on Form 3291.
(b) Films exposed abroad by a foreign concern or individual shall be previewed by a qualified employee of the Customs Service before release. In case such films are imported as undeveloped negatives exposed abroad, the approximate number of feet shall be ascertained by weighing before they are allowed to be developed and printed and such film shall be previewed by a qualified employee of the Customs Service after having been developed and printed.
(c) Any objectionable film shall be detained pending instructions from Headquarters, U.S. Customs Service or a decision of the court as to its final disposition.