From Popular Mechanics:
On February 12, an underground electrical transformer exploded in front of a Radio Shack on 6th Avenue, in New York City, emitting a fireball seven stories high and damaging nearby buildings. Here's how this could have happened.
A transformer from Consolidated Edison (Con Ed), New York City's sole electricity supplier, exploded from beneath the sidewalk in an underground vault yesterday, creating a fiery blast that shattered windows multiple stories high. Though no injuries were reported, offices and stores at the corner of 20th Street were left smoldering.
Investigators are still trying to answer the question: Just what lead this transformer to explode?
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