The source, but not the cause, of a liquefied natural gas (LNG) storage tank explosion and fire in Washington state has been found, a Salt Lake City-based spokesperson for Williams' Northwest Pipeline Co. told NGI on Friday. More definitive information is probably still 10 to 14 days away, she said.
During a community meeting in the Plymouth, WA, area where the natural gas storage facility is located, Northwest's Ed Brewer, vice president and operations general manager, said the preliminary investigation concluded that a rupture in one of the two storage tanks' pressure vessels was the source of the explosion and fire March 31 that injured five workers and required a partial evacuation of Plymouth residents (see Daily GPI, March 31).
Brewer said determining what caused the vessel to rupture is part of the ongoing investigation by the company, the state and the federal Pipeline and Hazardous Materials Safety Administration (PHMSA). In the meantime, Northwest is in a seven- or eight-day process of transferring the LNG in the damaged storage tank to the second one onsite, which was unaffected by the blast, the spokesperson said.
Each tank contained about one-third of their 1.2 Bcf-equivalent capacities. There are still no estimates on the extent of the damages or how long it will take to bring the storage facility back online, according to the spokesperson, who characterized the facility's current state as "heavily damaged."
There still is very little information coming from the investigation being led by PHMSA (see Daily GPI, April 2). Why the pressure vessel failed is still far from being answered. "We're still determining that, and when we find out all of the background and information about that, we will make that public,” the Northwest spokesperson said.
The spokesperson also reiterated that there was no leakage of LNG at the site. There was some gas and water vapor emitted, along with leaks of insulation material that is used between the inner and outer tank walls.
Additionally, the spokesperson underscored the fact that the plant's shutdown would have no impact on Northwest Pipeline's 4,000-mile interstate gas pipeline network in the Pacific Northwest.