When a bomb exploded beneath a government building in Oklahoma City on April 19, killing 168 people and sending tremors of fear throughout the nation, one of the most disturbing aspects of the terrorist act was that it was in at least two respects homegrown. Not only were the perpetrators thought to be U.S. citizens, but their devastating weapon was fashioned from the most ordinary of materials: fertilizer.
The event triggered a call to have fertilizer chemically treated so that it cannot be used for bombs. At issue is a common fertilizer based on ammonium nitrate. Almost any neighborhood do-it-yourself store stocks the stuff because it delivers nitrogen, in the form of nitrates, directly to plants without the intercession of soil bacteria. It also happens to be what bomb specialists call an oxidizer. When combined with a flammable material such as diesel fuel, it can supply the oxygen needed for ...
