Federal regulators recently sent a “warning letter” to the North Slope Borough regarding its natural gas pipeline serving the village of Nuiqsut.
In the May 23 letter, the U.S. Pipeline and Hazardous Materials Safety Administration told the borough an inspection conducted April 23-25 turned up “probable violations” of safety regulations.
The borough “failed to provide adequate cathodic protection for the Nuiqsut natural gas transmission pipeline ... for the years 2011 and 2012,” the letter said.
Cathodic protection is a technique for preventing corrosion.
The borough also failed to protect sections of the above-ground pipeline from the weather, PHMSA said.
Coating on the pipeline is damaged, specifically at U-bolt and stress point locations, to the extent that moisture has penetrated beneath the coating and corroded the pipe, the letter said.
“In some sections, the steel surface has corroded away and in some sections deep pitting could be observed,” the agency said.
In 2010, a services company performed a coating damage assessment on the pipeline, the letter said. Data from the report showed about 150 locations where coating damage had occurred, with corrosive moisture getting in.
“Many pipeline locations sustained damage, specifically at U-bolt locations, due to movement of the pipeline, which was caused by wind vibration and expansion and contraction of the pipeline,” the letter said.
Steep fines threatenedPHMSA said the borough was subject to a civil penalty of up to $200,000 for each day a violation persists.
“We have reviewed the circumstances and supporting documents involved in this case, and have decided not to conduct additional enforcement action or penalty assessment proceedings at this time,” the letter said. “We advise you to correct the item(s) identified in this letter. Failure to do so will result in the North Slope Borough being subject to additional enforcement action.”
The three-page letter was addressed to Charles Sakeagak, director of the North Slope Borough’s public works department. He couldn’t be reached for comment on the warning letter.
The borough is based in the village of Barrow.
The pipeline carries gas from the ConocoPhillips-operated Alpine field south to the Inupiat village of Nuiqsut.
The 14.4-mile pipeline is partly above ground and partly below. It went operational in September 2008.