All plastic explosives manufactured or imported on or after April 24, 1996, must contain a detection agent. (The importation of plastic explosives into the United States requires that the importer file ATF Form 6 certifying that the imported plastic explosives contain the required detection agent, or is exempted from the marking requirements as provided in the regulations). It unlawful to manufacture, import, transfer, receive, or possess any plastic explosive that does not contain a detection agent. Federal law enforcement agencies and the military may possess unmarked plastic explosives if they meet the affirmative defense requirements under 27 CFR 555.182.