Last-ditch talks are being held in a bid to avert strikes by firefighters at the Sellafield nuclear site.
The GMB union said the meeting on Thursday was the last chance to resolve a long-running row over pay.
GMB members have voted two to one in favour of a series of 24-hour strikes.
The dispute over pay grading has been going on for several years, during which time the GMB says firefighters have been performing roles above and beyond what they are paid to do, such as paramedic work.
GMB official Chris Jukes said: “Sellafield management are now at the door of the last chance saloon if they want to avert these strikes.
“The firefighters work above and beyond their pay grade to ensure the safety of tens of thousands on site, not to mention the wider public for miles around the site.
“After years of being underpaid, it’s time they were given their due.
“No-one wants to go on strike but we’ve been backed into a corner.”