A natural gas pipeline explosion in southern Kentucky this morning, paired with a spontaneous sinkhole at Bowling Green’s Corvette Museum yesterday, is providing fodder for the opposition to a proposed natural gas liquids pipeline.
Stephen Howard was near the southern end of Nelson County coyote hunting last night. That’s a good fifty miles away from where the explosion happened, but even so, he says the sky lit up orange. He watched it for awhile.
For people like Howard, who was already leery of the proposed Bluegrass Pipeline passing through Kentucky, learning that the fire was from a natural gas pipeline only made him more worried about the project.
Woodford County resident Bob Pekny feels the same way.
“We feel sort of vindicated that a lot of what we’ve been trying to tell people about the dangers of this are now being proven,” he says.
Pekny’s chief concerns about the Bluegrass Pipeline are the risk of explosion and the potential for widespread water contamination—and both concerns are illustrated by this week’s events in Bowling Green and Adair County.
First, it’s important to point out that the pipeline explosion earlier today was a natural gas transmission line: a 30 inch diameter pipe that carries natural gas across Kentucky. The proposed Bluegrass Pipeline—as well as conversion project by Mark West and Kinder Morgan of the Tennessee Gas Pipeline—would carry natural gas liquids. These are different products and are regulated under different federal laws, but both are flammable materials.
But safety is a concern. So, are concerns about and comparisons between these two pipelines valid?
A spokesman for Bluegrass Pipeline company Williams didn’t return a request for comment, but the Bluegrass Pipeline website tells concerned citizens that the pipeline will be periodically inspected “including leak surveys and valve and safety device inspections.” The company will also constantly monitor the pipeline remotely. Those are the same safety measures Columbia Gulf Transmission touts on its website.
The federal government is also responsible for periodic inspections, but a spokesman for the Pipeline and Hazardous Materials Safety Administration says there’s no set schedule. Sometimes a pipeline is inspected every year, but sometimes it takes 2-3. In the case of Columbia Gulf, which operates more than 3400 miles of pipelines in six states, the last federal inspection was in January 2012. Regulators spent 15 days on site. So, the most constant and comprehensive inspections are up to the companies, themselves.
But if a leak happened in the Bluegrass Pipeline, it would likely behave differently than last night’s natural gas explosion.
Natural gas is lighter than air. So during a rupture and explosion like that in Adair County, the gas (and subsequent fire) rises. When natural gas liquids leak, some remain liquids, and some are vaporized. Those that become gas are heavier than air, which means they hug the ground. And they can detonate on their own, which means a potential leak and explosion could be even more catastrophic.
Now, the sinkhole. The Bluegrass Pipeline will cross about 120 miles of karst terrain in Kentucky, where the underlying limestone makes caves and sinkholes common. Karst hydrogeologist (and former professor) Ralph Ewers says the prevalence of sinkholes in the areas is problematic for pipeline integrity.
“Crossing such areas subjects the pipeline to great stress,” he says. “Unusual stress. And stress, of course, leads to corrosion and to leaks.”
There are sinkholes in Kentucky’s karst areas all the time, though most don’t end up swallowing eight classic Corvettes, and thus don’t get very much media attention. But Ewers says it’s difficult to predict where a sinkhole will open up.
“What concerns me most is not the catastrophic rupture, though those are quite spectacular and they do cause considerable problems, it’s the more subtle ones I’m concerned about,” he says. “And a small leak would have consequences at distances of a mile away, ten miles away, before you understood that there was a leak at all.”
That’s because liquids can travel quickly through the limestone and caves that make up karst features. And as Williams officials revealed in last month’s hearing before Kentucky’s Environmental Quality Commission, the company’s system can detect a leak that’s 1.8 percent of the pipeline’s 24 hour flow. That number’s based on an average flow of 156,000 barrels, and officials estimate that means 2,808 barrels could leak before Williams is notified there’s a problem. Ewers says that liquid could have already traveled miles into the region’s groundwater supply.