Workers who lost their jobs at Vivergo’s Saltend site that include Scaffolders and other trades have until Wednesday evening to decide whether to accept a compensation package.
Almost 400 workers lost their jobs in March, when Vivergo terminated its contract with Redhall Engineering Services Ltd.
Through mediation group ACAS, Vivergo has offered almost £4,000 to each worker.
By accepting the offer, know as a COT3 agreement, workers will give up the right to bring further claims against the employer.
Les Dobbs, GMB union senior organiser, said: “We have told members we will support those who accept the compensation agreement, but we will also back those who wishing to continue to campaign to have their jobs back.”
The protests, which began in March, have caused severe traffic delays on several occasions, when workers blocked Hedon Road.