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A Decade Since The Praxair Explosion

June 24, 2015 Featured, History/Preservation No Comments

Twenty minutes past 3pm a decade ago today, a hot Friday afternoon, a massive series of explosions began at the Praxair facility on Chouteau, on the edge of the Lafayette Square neighborhood.

The burnt-out building in 2010
The burnt-out building in 2010

From the U.S. Chemical Safety and Hazard Investigation Board:

CSB investigators noted the accident occurred on a hot summer day with a high temperature of 97 degrees F in St. Louis. At Praxair, cylinders were stored in the open on asphalt, which radiated heat from the direct sunlight, raising the temperatures and pressure of the gas inside the cylinders. At approximately 3:20 p.m., a propylene cylinder pressure relief valve began venting. CSB investigators believe static electricity, created by escaping vapor and liquid, most likely ignited the leaking propylene.

Praxair security camera video shows the initial fire spreading quickly to other cylinders. Exploding cylinders – mostly acetylene – flew up to 800 feet away, damaged property, and started fires in the community. The fire could not be extinguished until most of the flammable gas cylinders were expended. An estimated 8,000 cylinders were destroyed in the fire, which took five hours to control.

The investigation determined that the pressure relief set points, specified in industry standards, are too low for propylene and may allow the gas to begin venting during hot weather – well below the pressures that could damage the cylinders. Not only are the specified set points too low for propylene, the CSB found some valves begin releasing gas even before the pressure reaches the set point. Each time a pressure relief valve opens, its performance deteriorates – making it more likely to vent gas at too low a pressure in the future. (One Year after Gas Cylinder Fire and Explosions at Praxair St. Louis, CSB Issues Safety Bulletin Focusing on Pressure-Relief Valve Standards and Good Safety Practices)

Their video explains it all very well:

Today, a decade later, the site remains vacant.

The former Mackay Place with the Praxair site on the right
The former Mackay Place with the Praxair site on the right

There has been proposals, but nothing has advanced to construction. Maybe a gas station will want to locate here to compete with the QuikTrip coming soon at Jefferson.

— Steve Patterson


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