Gas explosion at Mexico hospital caused by worn bolts on gas truck

FILE - In this Jan. 29, 2015 file photo, firefighters spray water on a gas truck that caused an explosion and killed five at a maternity and children's hospital in Cuajimalpa on the outskirts of Mexico City. Mexican officials said Monday, Feb. 16, 2015 that two worn-out bolts on the gas tanker truck caused a leak that resulted in the explosion. Experts said wire and Teflon tape had been improperly used on parts of the truck's valves, and Mexico City chief prosecutor Rodolfo Rios said one of the bolts was the wrong size, and the truck's gas meter had been altered to shortchange customers. (AP Photo, File) (The Associated Press)

FILE - In this Jan. 29, 2015 file photo, rescue workers search for survivors in the rubble of a maternity and children's hospital shattered by a gas tank truck explosion in Cuajimalpa on the outskirts of Mexico City. Mexican officials said Monday, Feb. 16, 2015 that two worn-out bolts on the gas tanker truck caused a leak that resulted in the explosion. Experts said wire and Teflon tape had been improperly used on parts of the truck's valves, and Mexico City chief prosecutor Rodolfo Rios said one of the bolts was the wrong size, and the truck's gas meter had been altered to shortchange customers. (AP Photo/Rebecca Blackwell, File) (The Associated Press)

Mexican officials say two worn-out bolts on a gas tanker truck caused a leak that resulted in a hospital explosion that killed five last month.

The results of the investigation again highlighted the unsafe conditions that many propane tankers operate under.

Mexico City chief prosecutor Rodolfo Rios said Monday that two bolts on a flange connected to the truck's pump cracked, allowing a gasket to partially blow out.

That caused a leak that later ignited. The subsequent explosion and fire collapsed most of the maternity hospital on Jan. 29.

Rios also noted that one of the bolts was the wrong size, and the truck's gas meter had been altered to shortchange customers.

Experts said wire and Teflon tape had been improperly used on parts of the truck's valves.