The Gorseinon plant employed 1,000 workers at its peak

The 3M factory in Gorseinon makes tapes, adhesives and aerosols but said it has experienced a decline in demand.

This was not a "temporary blip" said a manager who blamed rising costs for raw materials and a change in the markets.

The fact the factory had survived more than 50 years was a sign, he hoped, it could "rise again" to this challenge.

No similar review is planned at 3M's other Welsh factory in Bridgend which manufactures microbiology products for the food and environmental industry.

Employees at 3M Gorseinon, which opened in 1952, were briefed on the challenges facing the site on Monday, said a statement from the company.

Unions are also in talks with management.

Certainly the employees we have here are absolutely superb and we've managed to overcome many problems in the past Jim Loft, human resources manager

John Bowers, plant manager, said: "We are experiencing a decline in demand for our products and this has forced us to consider the medium to longer term future of the plant.

"Whilst we have identified some produce areas we believe will be sustainable over the longer term, there are also significant parts of the business facing real challenges going forward."

Jim Loft, human resources manager, said a major part of the factory's product range was made for manufacturers of disposable nappies.

Products include paper and adhesive items

He said: "We're being squeezed at the moment in these markets by both rises in costs for raw materials and energy as well as we're seeing a movement in the markets that's taking the manufacturers onto different nappy constructions.

"And that means that our products aren't being used by them in the same volumes."

'Peaks and troughs'

Asked whether he could rule out closure, he said they were less concerned about some areas of the plant than others but they were not ruling anything out or in at this stage.

But, he added: "I've certainly seen many changes here and we've responded and risen to the challenges, certain peaks and troughs as we've gone...a very long time, over 50 years the plant has been here.

"I'd like to think that that is a sign that we can rise again to this particular challenge.

"Certainly the employees we have here are absolutely superb and we've managed to overcome many problems in the past.

"So that leads me down the path of hoping that this significant business issue is something that we can work our way through together."

Mr Loft said they would initially deal with the short-term issue of the fall in volume and then work with the union groups to address longer-term issues.

He hoped that in around a month, they would have something "more significant" to tell employees.

The Gorseinon plant is the American company's oldest manufacturing facility outside the US.

3M employs 75,000 people around the world, including 3,850 at its 17 plants in the UK.