September25, 2008:  As terrorists increasingly use ammonium nitrate (a commonly used agricultural fertilizer) for their bombs (by mixing it with fuel oil and setting it off with a detonator), there has been a lot of research by chemical and fertilizer manufacturers to reformulate ammonium nitrate so that it will not so easily explod. The Honeywell corporation found that by adding some ammonium sulfate to the ammonium nitrate, you actually improve the fertilizing ability of the mix (by making the treated soil less acidic), and prevent the fertilizer from being used as an explosive. Actually, you can still use the ammonium sulfate nitrate mix as an explosive, but it requires some creative chemistry to do so, and serves as a technological barrier for most terrorist groups.

The military has long used ammonium nitrate as an explosive in large bombs (usually five tons or more of ammonium nitrate, fuel oil and powdered aluminum) and would continue to do so. But plain old ammonium nitrate would be reclassified as "military grade explosives material" and its sale would be restricted.