The Times Square bomber bought the wrong fertilizer

Unprofessional terrorist is unprofessional: apparently this is the main reason the bomb didn't go off.
The would-be car-bomber who left an SUV loaded with propane and gas cans, fireworks and timing devices on a Times Square street also had more than 100 pounds of fertilizer, but not the kind that would explode, police said today.

Instead of ammonium nitrate, the kind of fertilizer used by Oklahoma City bomber Timothy McVeigh, the person who abandoned the van on the crowded New York City street had a metal gun locker full of a harmless fertilizer, New York City Police Department spokesman Paul Browne said.

Sources also told ABC News that the valves on the propane tanks were not open, which would have made it less likely that the gas inside would have ignited.
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