Chemical firm Dow is set to cut nearly 300 jobs at its Barry works.
The chemical manufcaturing firm - one of the Vale's biggest employers - has confirmed it plans to close down the basics area at its Cardiff Road site within the next three or four years.
It's understood 291 workers are affected - around a third of the workforce at the Barry plant, which is expected to focus on making downstream silicones.
A consultation with employees is now underway with no redundancies expected until the middle of next year.
According to union officials, it's believed the corporation is blaming "cheap competiton" from China.
In a statement on Monday afternoon, a Dow spokesperson said: "As part of Dow’s assessment of its European assets, the company has identified the basics siloxanes operations at Barry, U.K. among other upstream portions of Dow’s portfolio that will require further action."
"The potential outcome identified at this time for Dow’s basics siloxanes operations at Barry is a shutdown."
The statement added: "Siloxanes production is one of several manufacturing facilities and operations at our Barry site, which in total employs approximately 850 employees and contractors."
"This potential shutdown would help strengthen the Company's competitive position in the specialty silicones market in Europe and the U.K."
"The production of specialty silicones in Barry will continue, supporting key markets such as automotive, electronics, energy, construction, and personal care."
The Unite union says its calling on the US-owned to reconsider its decision and work with them to avoid compulsory redundancies.
Unite secretary general Sharon Graham said: "It is outrageous that valued workers are being punished for a situation not of their control."
"The potential loss of so many well paid jobs in the area will be devastating, not just to our members and their families, but to the local economy as well."
The Barry works were opened in 1941, initially under the ownership of the Ocean Salts company. Dow Inc. arrived in 1971 when it took over the site from Midland Siicones and now employs around 850 people working around the clock.
Dow makes use of basic chemicals internally as raw materials, which are also sold worldwide in areas such as the food industry, paints and coatings and dry cleaning products.
In 2021, the corporation was ranked as among the three largest manufacturers of chemicals in the world - with 214 sites across 37 countries.
But according to the Unite union, Dow says its basics product are no longer competitive on the open market with China undercutting prices.
Unite regional officer Richard Jackson said: "Unite is calling on Dow to reconsider its decision and work with us, government and other stake holders to find an alternative solution to this closure."
"Unite is also calling on Dow to work with the union in order to avoid compulsory redundancies and to seek to protect as many jobs as possible. The union will ensure it is involved all the way throughout this process."
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