A "seriously ill" worker suspected of being infected with the Covid-19 virus was flown to shore by emergency helicopter from a UK oil facility in what coastguard described as a "life or death situation".
A coastguard search and rescue helicopter from Sumburgh in Shetland was used on Wednesday evening to pick up the person from a floating production, storage and offloading vessel west of the Shetlands.
A coastguard spokesperson told Upstream: "The HM Coastguard helicopter from Sumburgh was sent to an FPSO 80 miles (130 kilometres) west of Shetland yesterday evening (25 March) to pick up a person who was seriously ill and believed to have Covid-19.
"Our helicopters are used in life and death situations and while the majority of Covid-19 cases will not fall into that category, this one did."
The coastguard would not reveal the identity of the facility involved.
Multiple industry sources told Upstream it was the Aoka Mizu, operating on Hurricane Energy's Lancaster field.
However, this remains unconfirmed.
Hurricane Energy has been contacted for comment.
The coastguard spokesperson said the crew of the helicopter and the aircraft itself were "taken out of operational work" on their return to base.
New crew took duty at 1pm on Thursday.
"The crew are being quarantined and the helicopter deep cleaned at another location," the spokesperson said.
A secondary helicopter at Sumburgh is being be used to ensure emergency calls can be dealt with.