The British coast guard announced that over 500 workers were evacuated from an oil rig on Sunday by a fleet of 14 helicopters, including five Royal Air Force helicopters.

The evacuation occurred after a security incident. According to BBC News, the alarm was raised at 0915 GMT on an accommodation block, the Safe Scandinavia, which is attached by bridge to an oil rig in the Britannia field.

The Britannia field, discovered in the mid 1970s, is the first in the UK sector of the North Sea to be operated jointly by two companies, Conoco and Chevron, through the formation of the new operating company, Britannia Operator Limited.

Britannia, situated 210km (130 miles) north-east of Aberdeen, covers approximately 112km² (70 square miles).

The Safe Scandinavia, which is owned by Norwegian-based firm Pro-Safe, is a floating accommodation unit with 583 beds and it offers accommodation for workers from Britannia Operator Limited.

Britannia Operator Limited said reports were being investigated, while the relevant emergency authorities have been alerted.

“The company is doing everything possible to resolve the situation and to confirm details of the incident,” the company said in a statement.

The Press Association reported that the evacuation followed a bomb threat, but BBC News said

“it is in no way, shape or form related to terrorism”

However, an official from the Ministry of Defence said that the alert is over and the workers were now being returned to the rig.

Also, the Press Association informed that a 23-year-old British woman is being questioned by the Grampian Police, the local police force, following the security alert.

“Grampian Police can confirm it is meantime investigating an alleged incident on a North Sea installation. As part of the police inquiry into this matter arrangements are being made for a 23-year-old British woman to be taken on shore” the police said in statement, quoted by the Press Association.

Image Credit: ProSafe