The Humberto Vidal explosion (sometimes also referred to as the Río Piedras explosion) was a gas explosion that occurred on November 21, 1996 at the Humberto Vidal shoe store in Río Piedras, Puerto Rico. The explosion killed 33 and wounded 69 others when the building exploded, causing much of the interior of the building to collapse. It is one of the deadliest disasters to have occurred on the island.
Explosion
thumb|right|250px|A survivor is carried out after being rescued from the rubble.
The explosion occurred at about 8:35 a.m. on Thursday, November 21, 1996 in the middle of a bustling commercial sector of Río Piedras. The six-story building that housed the Humberto Vidal shoe store, a jewelry store, a music shop store and the head offices of Humberto Vidal was virtually destroyed; it was later demolished. A nearby school suffered no casualties.
The immediate theory was that the explosion was caused by a bomb planted by clandestine paramilitaries or even arson because of previous deliberate acts. However, there was no trace of explosives, nor were there flammable materials an arsonist could have used.
United States President Bill Clinton declared Puerto Rico a disaster area, which ensured the receipt of federal aid to help the victims, including the assistance of the National Transportation Safety Board (NTSB), which launched an investigation. San Juan Gas Company, owned by Enron Corporation, denied any responsibility, claiming that the building had no gas service at the time of the explosion.
Casualties
The explosion killed 33 victims and wounded 69 others. Most of the victims were inside the building at the moment of the explosion, but others were in the streets surrounding the building. After the explosion, bodies of victims were placed on the pavement in front of the nearby La Milagrosa church, where Cardinal Luis Aponte Martínez administered last rites. "There were just parts of bodies lying in the street, torsos, bones, cars blasted against the building," Police Chief Pedro Toledo said. The owners of the shoe store claimed that they had reported a gas leak to the San Juan Gas Company several days before the explosion.
Investigation
The NTSB's investigation revealed that several persons had reported a gas leak in the building in the days leading up to the explosion, complaining about a bad smell in the store's basement. The store had no gas supply, so another nearby gas line appeared to be the culprit. It was discovered that a gas pipe carrying the heavier-than-air propane gas was broken. A few years earlier, a water main was installed below, which bent the pipe in the process. When the pipe had been installed, it was tightly bent, adding to its stress levels. The addition of the water main caused it to break. The ignition source was found to be an air-conditioning switch with heated wiring.
According to a city resolution, all underground gas lines in Río Piedras were removed to avoid further tragedies.