“BP has told us the leak was almost entirely contained so this isn’t an environmental accident,” a PSA spokeswoman told Reuters on Wednesday. “But it was very serious because of its location, due to the danger to the facility.”

The oil and gas leak happened in the separator module on Ula’s production platform, resulting in a spill on the facility itself and forcing BP to evacuate personnel to the drilling platform, one of the three units that make up the facility.

The PSA’s investigation is expected to take months but BP can restart production at its own discretion once their own investigation and repairs ensure safe operation, the safety watchdog added.

BP announced on Tuesday that it suffered a leak at its Ula platform in the Norwegian North Sea on September 12 and shut the facility pending an investigation and repairs.

BP, still trying to rebuild its reputation after the 2010 Deepwater Horizon oil spill, America’s worst ever, declined to discuss the details of the incident on Wednesday and said it was working with authorities and needed more time to estimate the extent and time frame of repairs.

Ula, owned by operator BP (80 percent) and Denmark’s Dong (20 percent) is relatively small and mature, with production seen at 11 000 barrels per day this year.

BP, which is disputing charges related to the Macondo spill, was accused by the US Justice Department of gross negligence and wilful misconduct, a position that could lead to nearly $21 billion in civil damages if a federal judge agrees.