Industrial packaging firm Crown Packaging is planning to close its production facility in Neath Port Talbot due to overcapacity, which may leave 250 of its UK employees without job.
The production unit, known locally as 'The Box' and 'Metalbox', is used for manufacturing lids for cans.
The facility has been one of the largest local employers for 75 years, reports BBC.
In a statement Crown said: "We understand this will be a difficult time for all people associated with the Neath factory and we are actively meeting with all employees at the site to explain the proposal in further detail."
British trade union Unite and Crown Packaging has informed the government about the closure, and expects co-operation to support the employees.
Unite Wales secretary Andy Richards was quoted by ITV as saying: "This is a further body blow to the Welsh manufacturing sector and to Neath in particular, which has suffered a series of losses of significant employers in recent years.
"We call upon the Welsh Government to do everything in its power to intervene and to discuss with the company alternatives to plant closure."
Crown Packaging UK, a subsidiary of Crown Holdings, designs, manufactures, and sells beverage cans, food cans and aerosol cans among other products to be used across industries.
Image: Known as 'Metalbox' locally, the plant manufactures lids for cans. Photo: courtesy of twobee / FreeDigitalPhotos.net.