Unite general secretary Sharon Graham has called for urgent action to secure the future of the Rough gas-storage facility off East Yorkshire.
In a statement published on 15 October, the union warned that uncertainty over the site threatened skilled employment and Britain's energy resilience.
Unite estimates that closure could affect 100 direct jobs and a further 350 roles in the supply chain.
Graham said maintaining the facility was important for the country's ability to heat homes and sustain reliable energy supplies.
The union wants the government and Centrica to consider all options for keeping Rough operational, including possible public ownership.
It also argues that the site could contribute to the transition to cleaner energy through future hydrogen storage.
Unite's proposals are calls for intervention, not an announcement that ministers have agreed funding or ownership changes.
