Norway's oil regulator said on Friday it was investigating the causes of an outage earlier this month at Equinor's Hammerfest LNG plant in the north of the country.
The plant converts natural gas produced from the Arctic Snoehvit field into liquid natural gas (LNG) which is exported by tankers.
"Equinor shut down the plant on 11 March 2019 in order to repair deficiencies in a number of safety valves there. A total of 190 of these devices were missing heating cables and insulation," Petroleum Safety Authority Norway (PSA) said in a statement.
"This facility has been operated over time with weaknesses in its safety-critical equipment," it added.
Equinor's spokesman Morten Eek separately said the plant had since been restarted.
"The shutdown was unplanned but controlled, and repair work was conducted efficiently to get systems to meet the requirements, and production at the plant could then resume," Eek said.
He said the repair work was done after a recent evaluation showed a higher safety risk level compared to previous evaluations.
Equinor operates the plant and the Snohevit gas field, and its partners are Petoro, Total, Neptune Energy and DEA.
(Reporting by Nerijus Adomaitis, writing by Terje Solsvik, editing by Gwladys Fouche and Susan Fenton)
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