Gas explosion in the Humberto Vidal
In the gas explosion at Humberto Vidal in San Juan ( Puerto Rico ) on September 21, 1996 33 people were killed and 69 injured.
description
The accident happened in a five-story building on a street corner of Río Piedras , a suburb of San Juan, Puerto Rico. The building has belonged to the Humberto Vidal company since 1984 , who had their headquarters here and used the upper four floors as office space. Among other things, the company's shoe store was located on the ground floor of the building, while the basement served as a warehouse.
Days before the accident, customers of the store noticed a strange smell of gas. Since the building itself has no gas connection, the owner suspected a leak in a supply line outside the building and called the responsible gas supplier, the San Juan Gas Company , several times , but they could not find any leak.
Finally, on September 21, 1996, at 8:35 am, a gas explosion occurred, killing 33 people; 15 of them in the building and 18 outside. 69 other people were injured. The building partially collapsed as a result of the explosion; the lower floors collapsed, while the upper floors remained largely intact, where most of the survivors were ultimately located. Several neighboring buildings were severely damaged by the explosion. Since the explosion occurred in the early hours of the morning, when most of the shops on the otherwise busy shopping street were still closed, the accident turned out relatively lightly.
The cause of the explosion could no longer be determined; However, since routine maintenance was being carried out on the building's air conditioning system on the day of the accident , it is very likely that a spark produced when the fan motor was switched on triggered the explosion. In addition to the shopkeeper, the corpse of a technician who was maintaining the air conditioning in the building at the time could also be found in the building; Another technician had left the building shortly before the accident and thus avoided the disaster.
root cause
The National Transportation Safety Board began investigating the cause of the accident. After a fire or even a terrorist attack was initially suspected as the cause, it actually turned out that a gas leak in a nearby supply line had caused the accident.
In 1992, four years before the accident, a new water pipe was installed during road construction work, whereby the gas pipe not shown on the maps was damaged while backfilling the excavation pit, which has since leaked unnoticed. Later it turned out that there were no complete maps of the supply lines under the affected street because the government of Puerto Rico did not keep a corresponding cadastre, but each company was responsible for documenting its supply lines, which was not done adequately; The water pipeline installed subsequently was also not shown on the maps of the water supplier. The leak was not detected by the employees of the gas supplier due to a simple incorrect operation of their gas meter - they forgot to calibrate the device in the fresh air before taking the measurements in the building. Boreholes in the street could not detect the gas leak either, because at 46 centimeters they were not deep enough to detect the leak at a depth of 1.20 meters.
The gas company denied responsibility for the accident, claiming that methane leakage from the sewer system caused the explosion. But methane is lighter than air and would therefore have collected on the ceiling; Investigations at the scene of the accident found that the shoes of the shoe shop flew up against the ceiling, so the explosion must have occurred on the floor, which can only be explained by a gas heavier than air such as the propane used in the gas network of the supplier .
reception
The accident was shown in an episode of the broadcast seconds before the accident .
Web links
- NTSB investigation report on the accident (PDF; 1.5 MB)