Forensic Investigation Continues in Deadly Kansas City Gas Explosion

Image from www.twincities.com

Image from www.twincities.com

The cause of the recent Kansas City restaurant explosion is still undergoing forensic investigation. But what is shiny-diamond clear, is that the subcontractor suspected of rupturing the natural gas line didn’t have an approved permit for the work. The deadly fire left one dead and 15 others injured. Officials say Heartland Midwest struck a natural gas line doing underground work shortly before the explosion.

What Went Wrong?

While some natural gas explosions can take months to investigate, the incident in Kansas City is pretty cut and dry. When heavy equipment is used to dig in metropolitan areas, a utility locating company must be contacted from the onset to conduct a field search for buried electric and natural gas lines, and then clearly mark them with paint on the ground. As a general rule, heavy equipment cannot be used within approximately 1-foot of buried lines. Instead, the remaining soil close to the buried service lines must be hand dug with shovels to prevent the inadvertent cutting, fracturing, or puncturing of the service lines.

In the Kansas City case, it appears that heavy equipment used to dig (in an un-located area) caused a failure of the natural gas line, allowing natural gas to leak from the line. While natural gas is lighter than air, and much of it would have harmlessly entered into the atmosphere, some of the gas can travel underground through the disturbed soil and squeegee gravel which surrounds the buried line. This can often lead to natural gas entering a nearby building, in this case JJ’s restaurant, below grade at a foundation footing, filling the crawl space or basement of the building with natural gas.
Natural Gas Properties

To make matters worse, the odorant used in gas so that it can be detected by humans can be scrubbed from the gas by the soil as it travels underground, leaving the gas which enters the building odorless and undetectable to human’s natural senses. Once the fugitive gas reaches a sufficient concentration in the building (known as the lower explosive limit) and it is exposed to an ignition source, an explosion will result. A procedure known as bar-holing can be used to bore into the soil surrounding the leak to determine the underground pathway the fugitive gas took into the affected building, thus shedding additional light on the cause of the explosion.

Hours before JJ’s restaurant exploded, witnesses reported a strong smell of gas. Unfortunately, no one alerted the fire department about the potential gas leak until the subcontractor called 911 to report the ruptured gas line.

Who Handles the Investigation?

Enter…forensic petroleum engineering. The determination of the exact cause will require collaboration from utility officials, fire officials, and petroleum forensic engineers who will conduct investigations into potential mechanical & metallurgical breakdowns, electrical failures, high-pressure malfunctions, and OSHA compliance and regulations.
See how it happened:
http://www.youtube.com/watch?v=sCTvykfY7Uk

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