July 6, 2007 – 5:45 p.m.
When Darrell Taulbee first learned the 1995 terrorist bombing of the Oklahoma City federal building was carried out with a common fertilizer as an explosive, he got to work.
Toiling away at his coal research lab at the University of Kentucky, Taulbee has spent the intervening years trying to dilute ammonium nitrate to make it a less desirous tool for terrorists. Now, he believes he has found a way to coat the product with coal combustion byproducts to minimize its explosive power.
“We found that not only does it appear to be as effective in agriculture as a fertilizer, but it would have a longer shelf life” than pure ammonium nitrate, said Taulbee, a research scientist and industrial support coordinator at the school’s Center for Applied Energy Research.
The potential fix for the use of ammonium nitrate as an explosive device comes amid continuing debate in Washington over how to control the substance. Lawmakers are considering a measure to regulate the purchase and sale of the fertilizer via registration with the Department of Homeland Security.
Taulbee received a $125,000 grant from a DHS contractor, the National Institute for Hometown Security in Somerset, Ky., to research coating ammonium nitrate. He experimented with different concentrations, crafting makeshift bombs and gauging how much of the explosive power was suppressed.
He determined that a 20 percent ratio of coal ash to 80 percent ammonium nitrate prevented large blasts, even when the samples were crushed.
Between 1 million to 2 million tons of agricultural grade ammonium nitrate is produced each year, to provide crops with nitrogen, but sales have slowed in recent years amid liability concerns. Taulbee said at least one executive from an ammonium nitrate producer consulted on the project.
Farmers would have to use more fertilizer if it was coated, but he believes many would.
“I think most farmers are willing to make a small sacrifice, if it will mean their ammonium nitrate is safer,” he said.
Congress has been looking at ways to regulate ammonium nitrate, out of fear it could be used in a terrorist attack. The House Homeland Security Committee approved a bill (
Potential users would also be checked against federal terrorism watch lists.
A similar bill (
Kathy Mathers, vice president of public affairs for the Fertilizer Institute, the industry’s trade association, said several member companies are looking at similar ways to dilute or change ammonium nitrate to make it safer.
“We don’t discourage them from doing it, but it’s purely commercial in nature,” she said. “There’s a lot of things in research stages, but there’s nothing that we’ve pushed as an alternative to legislation.”
Taulbee said he thinks the government should focus on innovative solutions like his, instead of a registration program.
“I think the government should mandate [coating ammonium nitrate] because it gives maximum security,” he said. “If you sell it to someone with a license, it will be like illicit drugs. Someone is going to get their hands on it on the black market.”
He estimates that it would cost about $20 million a year for the government to subsidize the coating of ammonium nitrate with the ash, which is cheap and often winds up in landfills.
The government has also considered requiring that ammonium nitrate be diluted to a maximum of 80 percent, but Taulbee said diluted ammonium nitrate can still be enhanced by experts to be used as an explosive. Once the product is coated, it cannot be enhanced, as other scientists testing Taulbee’s work have found.
The University of Kentucky is exploring a patent on the product, but financial gain doesn’t seem likely. “If it can be used for the public good, we’d be fine with that,” he said.
Matthew E. Berger can be reached at mberger@cq.com.