Explosive Potential Tons of Explosives Disappear Each Year, Authorities Say By Pierre Thomas June 19 â€” Tons of explosives have been stolen in the United States over the last five years and no one can say for certain where much of the material has gone, law enforcement officials told ABCNEWS. It's a gap that has some of them losing sleep. It took about 3,000 pounds of the explosive ammonium nitrate to bring down the Murrah Federal Building in the deadly Oklahoma City bombing in 1995. Convicted bomber Timothy McVeigh is believed to have bought or stolen most of the explosives. Last year alone, 31,000 pounds of that same material were stolen from locations across the country. Most of it has not been recovered. Government officials acknowledge that significant quantities of potentially lethal explosives routinely disappear. "We're not talking about firecrackers, or bottle rockets, or anything like that," said Rep. Lamar Smith, R-Texas, chairman of the House Subcommittee on Crime, Terrorism and Homeland Security. "We're talking about large quantities of very dangerous explosives â€¦ that cannot be used in a benign way." High Explosives Stolen From January 1998 through December 2001, 27,000 pounds of high explosives â€” including dynamite â€” were stolen. Thieves have targeted construction sites, mining operations and demolition companies. And while some of the stolen explosives flow into a lucrative black market serving the construction industry, there is growing law enforcement concern about how easy it would be for terrorists to steal bomb-making elements. "We can't let the potential dangers that can arise from the misuse of those explosive go unchecked," said Bradley Buckles, director of the Bureau of Alcohol, Tobacco and Firearms. "We have to remain ever vigilant about how those explosives might be used." Feds Quiz Dealers In response to the Sept. 11 attacks, the ATF contacted 7,500 explosive dealers and users. They found more than 1,000 violations of record keeping and storage. The agency has ordered dealers to increase security and to report any losses. But under current federal law, it is just as easy to buy explosives as it is to buy guns. Anyone â€” even noncitizens â€” can buy as much explosives as they want â€” without a background check. "It's literally easier to buy a ton of explosives than it is to buy a small-caliber pistol," said Smith. Congress is moving to increase the restrictions on explosives and close the loopholes in the law.