Workers at an oil refinery are to be asked if they want to vote for strikes in a dispute over pensions.
Around 350 members of Unite at the Essar Stanlow plant in Ellesmere Port are taking part in a consultative ballot.
Depending on the outcome, Unite could launch an industrial action ballot next month.
The union is in dispute over an increase in members’ contributions to the final salary pension scheme following a consultation.
Unite convenor Paul Robinson said: “Our members have made it clear that the proposals put forward by Stanlow to increase the pension contribution rate for workers are unacceptable.
“The company can easily afford the increase in pension costs. It is 35 years since the last industrial action at Stanlow and industrial relations have been excellent for many years.”