Police in Colorado Springs say they are investigating the disappearance of 400 pounds of ammonium nitrate---which already had been mixed with diesel in preparation for blasting.

Authorities say the substance still needs to be mixed with another agent and triggered by a blasting cap but they declined to provide more information. Experts did say that this amount, if detonated, could destroy a two-or three-story parking ramp.

A spokesman for the police department says the theft was reported Monday when workers arrived at Castle Concrete, which uses it for its quarry operations.

Ammonium nitrate is commonly used for blasting and was a key ingredient in the bomb that exploded at the federal building in Oklahoma City in 1995. That blast was estimated to involved about 4,000 pounds.

Authorities say the ammonium nitrate was taken from a semitrailer at the Castle Concrete site, where a padlock had been broken off the truck. It's packaged in 50-pound bags that officials say could easily be loaded in a car.

Authorities described the substance as looking like laundry detergent with a slight pink tint. It has a heavy odor of diesel and the bags are brown paper and say Buckley Powder A-N-F-O.

If you have any information regarding this theft, you're urged to call Colorado Springs Crime Stoppers at 634-STOP.