More than 12 years after Timothy J. McVeigh used ammonium nitrate fertilizer to blow up the Oklahoma City federal building, Congress quietly passed legislation this month to regulate sales of the explosive, reports The Los Angeles Times.

But the Secure Handling of Ammonium Nitrate Act of 2007, part of an appropriations measure signed by President Bush, falls far short of the strict law that some in the counter-terrorism community and federal law enforcement were hoping for.

"The bill really does not guarantee anything for the security of the citizens of the United States," says Bill Albright, a Defense Department consultant who spent his career at what is now known as the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).

According to The Times, the law, which the fertilizer industry supported, leaves the United States with weaker controls on ammonium nitrate than Britain, Germany, Australia, Israel, Saudi Arabia and many other nations.

Ammonium nitrate has been used in terrorist bombings around the world, including the attacks on U.S. embassies in Tanzania and Kenya in 1998.

Because of last-minute revisions to the legislation, many federal officials and outside experts -- and even some members of Congress -- are uncertain exactly what it mandates.

The Department of Homeland Security "is still reviewing the new law and considering how to harmonize it with existing chemical facility rules," an agency spokeswoman told the newspaper.

The measure requires licensing for ammonium nitrate facilities, registration for purchasers, and a framework for establishing what forms of ammonium nitrate will be regulated -- but leaves the specifics up to bureaucrats to decide later.

Clamping down on ammonium nitrate has taken years longer than it did to tighten controls on other explosives, nuclear materials, airport security and a range of other potential security weaknesses.

About 8 billion pounds of ammonium nitrate is used in the United States annually, split about evenly between the agriculture and explosives industries, according to business and government figures.

The main sponsor of the bill was House Homeland Security Committee Chairman Bennie Thompson (D-Miss.). Mississippi is one of the nation's largest producers of ammonium nitrate, according to the Fertilizer Institute, a trade group based in Washington.

"This bill will allow DHS to regulate the sale and purchase of ammonium nitrate in order to keep it out of the hands of terrorists while allowing it to be continually available for agriculture use," said Thompson, whose panel has jurisdiction over the department.