Sen. Thad Cochran, R-Miss, has introduced legislation that would require the Department of Homeland Security (DHS) to monitor sales of ammonium nitrate, an over-the-counter fertilizer that can easily be transformed into a powerful bomb, such as the one that destroyed the Oklahoma City federal building 10 years ago.

Cochran, chairman of the Senate Appropriations Committee, wants to make fertilizer producers and distributors register with their state agriculture departments and maintain sales records. Buyers would have to register with state officials before making purchases. DHS would be responsible for inspecting distribution centers and storage facilities.

Just three states regulate the sale of ammonium nitrate — Nevada, South Carolina and Oklahoma. Legislators in a number of states, including Maryland, Michigan, New York and California, have introduced bills to do the same.

The Oklahoma City bombing — in which Timothy McVeigh used 4,800 pounds of ammonium nitrate to blow up the Alfred P. Murrah Federal Building — prompted Congress to order the National Academy of Sciences (NAS) to examine ways to reduce the threat of terrorist bombings.

In 1998, a committee of NAS-appointed experts issued a report calling ammonium nitrate “by far the most commonly accessible explosive material.” The material was also used in the 1993 World Trade Center bombing, which killed six people, and the 2002 bombing of a Bali nightclub, which killed more than 200. Experts say the material is also used by insurgents in Iraq.

The NAS committee recommended prohibiting the retail sale of the fertilizer unless consumers provided identification and sellers kept records of transactions.

Edward Arnett, a chemistry professor at Duke University and co-chairman of the NAS committee, said that aside from a handful of state laws, there has been little regulation of ammonium nitrate.

“We’re not asking a whole lot,” Arnett said in a telephone interview Monday. He called Cochran’s bill “certainly a step, which is better than no steps.”

Until Cochran introduced his legislation, Rep. Maurice D. Hinchey, D-N.Y, had been the only member of Congress to propose a national policy. Hinchey introduced a bill (HR 1389) in mid-March that would set up a licensing system for ammonium nitrate sales, to be managed by the Justice Department.

“Voluntary efforts by industry groups to control the sale of ammonium nitrate are a good first step, but the risk of this deadly chemical getting into the hands of terrorists is too great to sit back, say that enough has been done, and not impose federal regulations,” Hinchey said in a prepared statement at the time.

Wendy Darwell, Hinchey’s chief of staff, said Monday that although Cochran’s bill is different from Hinchey’s, “we are happy to see the Senate have a similar bill to reach the same results.”

The Fertilizer Institute, a trade group representing the fertilizer industry, issued a statement supporting the Cochran bill, calling it an extension of a voluntary record-keeping program it has organized among its members.

A spokeswoman for the institute could not be reached for comment.

Cochran’s bill is cosponsored by Sens. Mark Pryor, D-Ark., Saxby Chambliss, R-Ga., and Pat Roberts, R-Kan.

Sean Madigan can be reached at smadigan@cq.com.