You might not know it but fertilizer is the explosive of choice for budget-conscious terrorists. The blasts at the World Trade Center in 1993, Oklahoma City Federal Building in 1995 and on rush-hour London buses and trains in 2005 all contained ammonium nitrate fertilizer (which is manufactured in bulk as an explosive by the U.S. and other countries as well as by companies.)

But what's an honest farmer to do? Well, Honeywell International—the Morristown, N.J.–based company probably most famous for your thermostat and home security system—has now developed a patented blast-free fertilizer that nullifies any explosive intent.

The company has been producing ammonium sulfate—another fertilizer—for 50 years as a by-product of making the nylon in everything from carpets to golf shirts. And tests since 1999 have shown that by combining ammonium sulfate with ammonium nitrate, the fast-acting fertilizer also used as a bomb, the latter gets bound up in the more stable variety. (Ammonium sulfate is inert enough to be used in some applications as a flame retardant.) "Whatever is trying to happen to the nitrate has to happen to the sulfate simultaneously…. It's the difference between lighting a wood log on fire and [igniting] a gallon of gasoline," says Jim Kweeder, principal research engineer at Honeywell Resins and Chemicals. "With an explosive, speed is everything. Slow it down and it's not an explosive anymore."

The Bureau of Alcohol, Tobacco and Firearms has tested the fertilizer and the U.S. Department of Homeland Security has certified it as a nonexplosive alternative based on the fact that it doesn't explode even when mixed with diesel or other fuels. What remains to be seen is whether it performs well as fertilizer. "Target crops for this product would be plants that do react to fast-acting nitrate but also plants that do need sulfate," such as tomatoes, cabbages, potatoes and even citrus trees, says Mark Murray, director of strategic marketing at Honeywell Resins and Chemicals. "It has the benefits of both fertilizers and negates the downsides from a safety and handling perspective" based on small field trials.

The company expects to begin offering the product by the end of 2009. Farmers will likely pay more for the so-called Sulf-N 26 fertilizer than the regular stuff, though prices have yet to be determined. The average price tag for ordinary fertilizer is presently more than $450 per ton. "On a ton of nitrogen [content] basis we will be charging a premium," Murray says. It is also not likely to replace all ammonium nitrate manufactured or used anytime soon, he admits. But those farmers who do use it will have some certainty that Homeland Security won't come calling when they buy in bulk.