Natural gas pipeline explodes – corrosion a possible cause

Natural gas represents 31% of the total primary energy consumption for the U.S., according to the U.S. Energy Information Administration. In terms of consumption, the electric power sector leverages the most natural gas at 35% of its total use, while industrial falls closely behind at 35%. The next highest usage is residential at 17%.

Despite its necessity for heating buildings and generating electricity, natural gas pipelines are susceptible to corrosion, which may result in serious accidents. For this reason, it is vital for natural gas providers to do all that they can to fight rust and decay on their pipelines to avoid property damage, injury or worse.

Explosion in central Kentucky
In the early morning hours of Aug. 1, a regional gas pipeline exploded, causing a major explosion, which killed one person and hospitalized five others in Lincoln County, Kentucky, CBS News reported. The explosion destroyed railroad tracks and forced the evacuation of dozens of individuals who resided in a nearby trailer park.

According to a WKYT meteorologist, the blast was so large that it showed up on station's radar. Numerous residents in nearby counties captured photos and videos of the 300-foot flames.

The Texas Eastern Transmission pipeline is owned and operated by Enbridge. Soon after the explosion, an Enbridge Spokesman Michael Barnes reported that the company was closely monitoring the situation, per The Associated Press.

"Our first concern is for all of those impacted by this incident and ensuring the safety of the community," he continued in his statement. "We are working with emergency managers to secure the site and have isolated the affected section of pipeline."

The multinational company had another natural gas pipeline on the same system explode in Ohio earlier this year, according to Reuters, while another pipeline caught fire in British Columbia, Canada, in Nov. 2018.

What caused the explosion?
While an investigation is still being conducted into possible causes, the Pipeline and Hazardous Materials Safety Administration received 38 reports of "significant" or "serious" issues about the pipeline since 2011. Corrosion was a contributing factor in almost half of these cases, according to 89.3 WFPL.

Regarding the investigation, NTSB senior accident investigator Mike Hiller told the public, "Our mission is to understand not just what happened, but why it happened and to recommend changes to prevent it from reoccurring."

Two local experts believe that a black shale rock formation may have caused or contributed to pipeline corrosion. This corrosion may have lead to the intense blast, where 30 feet of pipeline was launched into the air. 

Warren Anderson, a retired geochemist who specializes in black shale, told WFPL that he is confident that the explosion occurred within a black shale outcrop. This type of rock sometimes contains pyrite, which can cause corrosive issues.

"This is not the last one. There will be others and I can't say they are going to occur in more frequency, but this is definitely not the last one," said Warren.

Federal officials estimate that the investigation may take anywhere from 12 to 18 months to complete, according to the Courier Journal. In the meantime, 20 to 25 of the initially displaced residents in the area have no homes to go back to.

"We are letting homeowners go, accompanied by law enforcement, into their residence just to secure or obtain medicine or clothing or whatever they need," said Lincoln County Emergency Management Director Don Gilliam. "They will not be able to stay there. It's just not considered secure at this point."

Pipeline corrosion problems
When properly maintained and monitored, pipelines perform a vital role in transporting natural gas across the country for energy providers, according to a report from ASM International. As these pipelines are buried, the general public is typically not aware of their presence, until incidents like the Kentucky explosion take place.

In many cases, corrosion is responsible for leakages and accidents for natural gas pipelines. One of the major contributing factors to external corrosion of underground pipelines is inadequate coating. Internal corrosion may occur when water and contaminants in the gas erode the pipe wall.

In one 2018 study about corrosion failure of pipelines due to oxygen absorption corrosion and CO2 corrosion, the researchers wrote that relevant research is needed improve pipeline safety and measures must be taken as a result of this research.

Ultimately, the first step toward eliminating further accidents, like the Kentucky pipeline explosion, is to be proactive about corrosion testing and pipeline maintenance. Fighting corrosion before it becomes a serious problem is key to reducing the risk of tragic incidents recurring.