The ingredients for the type of fertilizer bomb used in the Oklahoma City bombing, and apparently in the recent deadly terrorist bombing in Oslo, Norway, continue to be widely available in Oklahoma and elsewhere.
The bombs are easy to produce with the proper ingredients, mainly ammonium nitrate, one of the most common fertilizers in the U.S., and fuel.
Timothy McVeigh used those same ingredients 16 years ago to build the bomb he exploded at the Alfred P. Murrah Federal Building. The attack resulted in the deaths of 168 people.
Norwegian Anders Behring Breivik, 32, is alleged to have used a similar concoction Friday to bomb the country's capital, killing eight people, before he went on a shooting spree and killed another 68.
Ammonium nitrate fertilizer has been used frequently in terrorist acts around the world, but little has been done in this country to restrict its use.
That's because this fertilizer and other components a terrorist would use to make a homemade bomb have legitimate uses, too, said Barry Black, a bomb expert with the FBI in Oklahoma City.
Black was also on the front line of the investigation into the Oklahoma City bombing in 1995.