Enstar Natural Gas has identified the problem leading to gas explosions that destroyed two houses, and a fire that claimed two more, on Lilac Lane in Kenai following the magnitude 7.1 earthquake in January.
According to an incident report filed Feb. 24 with the Pipeline and Hazardous Materials Safety Administration and the Regulatory Commission of Alaska, a main line separated at a weld joint and released 406,000 cubic feet of natural gas. The report doesn’t cite any corrosion or preexisting problem with the line.
“But for the earthquake, there wouldn’t have been any damage to the line at all,” said Lindsay Hobson, a spokeswoman for the company. “So the earthquake moved the line and we had the resulting release of gas.”
The 1.25-inch-diamater steel main line was installed in 1969. Hobson said that isn’t an unusual age for pipeline in Enstar’s system.
“We have newer portions of our line, especially down in Homer,” Hobson said. “But we are routinely monitoring our lines, checking for corrosion, checking for leaks and performing maintenance on our line to make sure that we continue to deliver safe and reliable service to our customers.”
The initial report of a gas explosion and fire came in at 2:25 a.m. Jan. 24, in front of 1213 Lilac Lane, following the quake that rattled Southcentral Alaska at 1:30 a.m. The report states that an Enstar crew was on site in 13 minutes. Hobson said there’s a crew standing by 24 hours at day, seven days a week at the Enstar office in Soldotna.
“The quick response by Enstar, and all first responders, was greatly appreciated, and they put forth a great effort, worked diligently, 24 hours a day for the first several days following the earthquake,” said Hobson.
It took until 2 p.m., though, to shut gas off in the area — nearly 12 hours after the call came in. In that time, 80 residents in the area were evacuated, and a second gas explosion destroyed the house next door, at 1215 Lilac. The resulting fire destroyed the two homes on either side, at 1211 and 1217 Lilac, as well. There were no injuries or fatalities to residents or emergency workers.
The report lists $550,000 in damage to the properties. Enstar estimates its own costs at $125,000 in property damage, repairs and personnel time.
Hobson said several factors contributed to the delay in shutting off the gas. Usually, when Enstar is called out on a leak, it’s because someone damaged a line while excavating during a construction project.
“And, so, when we arrive the ground is already exposed, we know exactly where the leak is and it’s already been excavated,” Hobson said. “And it’s very easy in those circumstances to shut off a flow of gas in order to make the needed repair.”
But in this case, Enstar first had to find the leak from above ground, then do its own utility locates to make sure their crew wasn’t going to hit any water lines or cables, then dig down 8 feet to the gas main.
“And, of course, this is January, and the soil is frozen and so we had to dig through that frozen earth to get to that line,” Hobson said.
The report states that gas to the main was shut off at three tie-in points from the street. The leak in the main was repaired and service restored to non-affected homes by 6 p.m.
Following the quake, Enstar did a system-wide leak survey. One was found in the Mountain View neighborhood of Anchorage, and it was repaired the same day. Enstar also got an uptick in calls from people reporting possible gas leaks, which Hobson said was likely due to increased awareness.
“We did have a number of calls come in the following weeks, but I think it’s pretty safe to say few, if any, of those were actually caused by the earthquake,” said Hobson. “It was just the public awareness about, ‘These are the signs of natural gas leaks and please call us if you see any damage to your appliances or smell gas or hear a hissing sound.’ It really was a good reminder for people to do that safety check, and the great news is that we have that many fewer leaks right now.”
She said Enstar is continuing to monitor the Lilac Lane area to make sure gas concentration levels stay at zero.
“Safety is the No. 1 priority for Enstar, and our response and our diligence leading up to and following the earthquake is certainly reflective of that value,” Hobson said.
If anyone suspects a gas leak, call the 24-hour report line at 1-844-SMELL-GAS.