NIHS Release

Lexington Herald-Leader (KY)
2007-07-05
Section: City&Region
Edition: Final
Page: C1

UK RESEARCHER TRIES TO MAKE FERTILIZER SAFER
VOLATILE AMMONIUM NITRATE IS COATED WITH COAL ASH
Sean Rose
Srose@herald-Leader.Com

Taking cover behind a pile of logs with pieces of quarter-inch steel shrapnel cutting through trees over his head, Darrell Taulbee first saw indications that he had made fertilizer safer. The University of Kentucky researcher was conducting test blasts of homemade bombs last summer in rural Breathitt County. The bombs were made from fertilizer with ammonium nitrate, the same substance used in the Oklahoma City bombing in 1995. But Taulbee wasn't looking for a big bang. Instead, he developed a way to coat the ammonium nitrate with coal ash, diluting the material and lessening the explosions. Taulbee thinks his method could stop the substance from being used for bombs and keep the fertilizer in farmers' hands. "It's so cheap, it's so readily available and it's so powerful, they have to do something," Taulbee said.

Shortly after the attack, Taulbee thought of adding coal ash, a byproduct of coal-burning electric plants, to dilute the explosive chemical. He had to wait for funds from the National Institute of Hometown Security in Somerset, a contractor for the Department of Homeland Security, and tested his theory over the past two years. He found that a mix of 20 percent coal ash to 80 percent of ammonium nitrate would keep an explosion from burning through all its fuel, making the blast far weaker than unmixed fertilizer. Greater concentrations of ash further weaken the explosion's strength. Two of the biggest advantages of coal ash over other dilution substances are that it's non-toxic and cheap. Mass quantities and near-zero demand for it mean one ton of coal ash can be bought for about $5, Taulbee said. Keeping the cost down is important because Taulbee wants the fertilizer to remain affordable and still be beneficial to crops. "It doesn't do any good to stop the explosion if it hurts the agriculture," he said. "That's its purpose."

Some heavy metals that could be in coal ash could damage crops, but at just a 20 percent mix, it would be something to monitor rather than worry about, said Wilbur Frye, executive director of the office of consumer and environmental protection in the Kentucky Department of Agriculture. Ammonium nitrate supplies crops with nitrogen, an essential chemical in farming. It's applied topically as opposed to being injected into the ground. It has the advantage over other fertilizers of not losing nitrogen when exposed to air for longer periods of time, Frye said.

Urea is another common fertilizer in Central Kentucky and has a greater concentration of nitrogen but is also more expensive, between $450 and $500 a ton, compared with ammonium nitrate at $350 to $400 a ton, said Mark Southworth, 29-year manager of Southern States, a farm supply store, in Lexington. Urea also needs rain to carry the nitrogen to the plant and loses its nitrogen if applied during dry spells.

Liquid nitrogen fertilizers are another fertilizer option used more in Western Kentucky, said Greg Simpson, a manager of a Southern States in Owensboro for seven years. Liquid nitrogen costs $330 a ton but requires more expensive equipment to inject it into the ground. Lexington farmer Bob James estimated that nearly half the fertilizer used in the region contains ammonium nitrate. He said he used about 50 tons of ammonium nitrate this year. Fewer manufacturers make ammonium nitrate now because of liability reasons, Taulbee and James said. Safer fertilizer could mean more manufacturers might make it again. "If they can get the ash mixed, it could be a cost effective thing to do because it would not be a high risk commodity to handle," James said. Southworth said making the product safer would make it easier to sell. "If it will be cost effective and if it will eliminate some of the hazardous material restrictions that ammonium nitrate has, then it could be a player," Southworth said.

Adding coal ash could also save the fertilizer from being banned by the federal government, which has been considered in the past, Frye said. Not everyone agrees that the ash addition would be a benefit to farmers, though. Lexington farmer Jim Barton said the ash would mean an extra step in the fertilizer's production, increasing the cost. "The big problem I see is that it's going to be another process," Barton said. "Every time you handle something, it adds to the cost." Frye agreed. Besides the possibility of more manufacturers, he said, he could see "no economic advantage to the farmers." If new regulation is necessary, Barton, who said he used 150 tons of ammonium nitrate this year, favored requiring a license to purchase and transport the fertilizer, similar to what's done with pesticides and insecticides. "A licensing thing probably would be better initially," he said. "I think it'd be less expensive." James called more licensing too extensive and too much trouble for the average farmer. Taulbee doesn't see licensing as a solution either. "It's like illicit drugs," Taulbee said. "If it's out there, someone will get their hands on it."

There's still a long way to go before the technology could leap to the public. Taulbee is looking for additional funding for further research. He'll follow up on testing the agricultural side, making sure the fertilizer will still benefit crops and turn more extensive blast testing over to federal agencies like the Bureau of Alcohol, Tobacco, Firearms and Explosives. He is confident his findings will hold up. "We'll just hand it over to those guys and say 'Here, see if you can make it blow up,'" he said. Taulbee is applying for another grant from the National Institute of Hometown Security. He hopes to hear back within six months. "It has the potential of worldwide application," said Ewell Balltrip, president of the institute.

Reach Sean Rose at (859) 231-3266 or 1-800-950-6397, Ext. 3266. See videos showing the experimental explosions on Kentucky.com.

by TRICIA SPAULDING , tspaulding@herald-leader.com - University of Kentucky researcher Darrell Taulbee tested his project on steel tubes to find the right mix for a less explosive product.