A union boss has called on operator EnQuest to be transparent about any structural issues with its Thistle platform in the North Sea.
EnQuest evacuated all 115 crew members yesterday after a “subsea structural inspection” of the installation around 125 miles north-east of Shetland.
The operator has since said a “support structure” for a redundant subsea storage tank led to the evacuation of workers to the nearby Dunlin platform, who are now being flown home.
The Health and Safety Executive (HSE) has confirmed it is investigating.
It is one of the few times that a platform has been down-manned due to structural concerns.
In 2017 CNR International’s Ninian South was evacuated ahead of a storm “to safely manage the structural integrity of the Ninian Southern jacket”.
That year Repsol Sinopec Resources UK (RSRUK) also agreed to suspend output from the now-decommissioned Buchan Alpha platform as the HSE had concerns about fatigue in the rig’s legs.
RMT regional officer Jake Molloy described the Thistle situation as “highly unusual” with the potential for an “extensive intervention” by subsea teams to assess the integrity issue.
He said any findings should be widely shared with the industry for any other older platforms which may have similar issues.
Mr Molloy added: “This is an old, old platform, it’s past its sell by date and it has problems.
“Offshore workers tend to put things in the category of black or white rather than this grey area which industry tends to utilise. So if it is a structural integrity issue, just like working on a scaffold, it’s not structurally sound so you have to come off it because it could collapse.
“But all of that said, we have got to give them time to put the subsea teams together, to do the investigations, to do the testing and come back and report.
“That report, we suggest, should be completely transparent in terms of the workforce and the regulators at least.
“But moreover this is an opportunity for EnQuest to step up and do that whole learning piece which the industry says it promotes so much.
“Let’s share the findings because there’s lots of old steel jacket structures out there so if there’s learnings to be gained from what’s happening with Thistle then let’s get it out there and share it with industry.
“Maybe interventions and checks can be done on some of the old structures.”
A coastguard helicopter from Sumburgh and two other aircraft from Norway assisted the evacuation yesterday.
All workers were safely accounted for.
The Thistle platform was first installed in 1976 and was dubbed by workers as the “Black Pig” by workers in the 1980s due to a heavy black cloud around it due to flaring.
It has since been rebranded the “Green Pig” as successive owners have cleaned up its operations.