WASHINGTON – More than six years after Timothy McVeigh used a truckload of fertilizer to destroy the Oklahoma City federal building, you still don't need a license or even personal identification to buy the material.
McVeigh used two tons of ammonium nitrate, which is commonly applied to wheat and pasture crops, and mixed it with a motor fuel to make a cheap but powerful explosive. Recipes for such bombs have circulated widely for years.
Three years ago, the National Academy of Sciences recommended banning sales of packaged ammonium nitrate unless dealers required IDs from buyers and kept accurate records. It laid additional steps if terrorism threats increased, including putting chemical markers in fertilizer to aid bomb-sensing equipment and licensing fertilizer dealers.
Little has been done since then, largely because of opposition from agriculture interests and the fertilizer industry.
"The regulatory issues were considered to be very costly for American agriculture, which was being challenged at that stage and still is," said Marye Anne Fox, a chemist who co-chaired the study for the science academy's National Research Council.
In light of last month's terrorist attacks, the fertilizer industry is reconsidering its stance.
"September 11th changed the landscape for a whole host of businesses," said Kathy Mathers, a spokeswoman for the Fertilizer Institute. "It's safe to say that all these will be on the menu for discussions in the immediate future."
Fox, chancellor at North Carolina State University, agreed that "the mood is much different now."
"The question politically is whether that's a sufficiently increased threat to mandate the restrictions on our freedom," she said.
The Treasury Department agency that regulates explosives -- the Bureau of Alcohol, Tobacco and Firearms -- has been studying the ammonium nitrate issue since 1996 but has yet to release a final report.
After Sept. 11, the agency put out a general alert to the explosives industry, but not to fertilizer companies.
"It looks like the industry has done a pretty good job of screening their own sales and watching the safety of their own product and the security of the storage," said ATF spokesman Jim Crandall.
Fertilizer distributors say they have stepped up their education of employees and doublechecked fences and storage facilities to prevent thefts. The Fertilizer Institute has an ongoing security awareness program aimed at dealers, distributors and haulers. A toll-free phone number is provided to report suspicious activity to the ATF.
Agriliance LLC, one of the biggest distributors of farm chemicals, ordered new rounds of security employee training and required supervisors to sign affidavits vouching that the sessions had taken place.
Agriliance, based in St. Paul, Minn., has 70 distribution and retail facilities. Store employees know their buyers personally so they don't need to ask for identification, said Kent Kutnink, the company's regulatory manager. "They have a very defined trade area; all our locations do."
Fox of the research council said methods of rendering ammonium nitrate inert have proven either ineffective or too costly. Such an additive must be nontoxic and yet difficult to remove from the fertilizer.
"That is always a challenge," said Amit Roy, president of the International Fertilizer Development Center, a nonprofit research organization.
To deter terrorists in Northern Ireland, Britain once required clay to be added to fertilizer, but bombmakers simply removed the clay and had a purer form of the ammonium nitrate.
Studies have found no practical additive, or taggant, that could be put in fertilizer to aid investigators in tracking down the perpetrators after a bombing. However, the fertilizer development center has developed a method of tracing ammonium nitrate to its manufacturer.
There are fewer than 15 manufacturers in the United States, Roy said. About 1.6 million tons of ammonium nitrate are sold annually. A ton sells for about $200.