Last week’s shock announcement about company restructure has left Chevron workers with an anxious wait to hear any final decisions, which could result in hundreds of job losses.

Chevron has said that a less complex and smaller downstream operation, requiring fewer positions and people, will be created.

Chevron’s global media relations spokesman Lloyd Avram said: “More information on the new organisation will be available in the coming months. The organisation will be complete and in place by the third quarter.

“Chevron’s global downstream asset portfolio undergoes continual review. No further decisions regarding assets or markets have been made.”

Carmarthen West and South Pembrokeshire MP Nick Ainger, met with management last week and was quick to allay fears that the Pembroke plant is at risk.

Mr Ainger said: “It is a global announcement, it doesn’t mention any refineries at all.

“The announcement that was made does not threaten Pembroke. The aim is to reduce the company overheads in its organisation while they are going through this period of low profitability, so they can keep refineries like Pembroke open.”

Preseli Pembrokeshire AM Paul Davies is joining colleagues in pressing Chevron’s head office in California for more details as soon as possible, as well as stressing the importance of the refinery to Pembrokeshire and Wales.

“This news is of huge concern. Chevron has said it won’t make any more detailed announcements for at least another five weeks, so the 1,400 workers now face a very stressful time waiting to hear what the future holds,” added Mr Davies.

The Welsh Assembly is being urged to take pre-emptive action to ensure the future of Pembrokeshire’s refinery.

South Pembrokeshire AM Angela Burns has written to the Deputy First Minister, Iuean Wyn Jones, stating that quick action must be taken.

“The Welsh Assembly needs to ensure that Chevron understands the importance of the company within Pembrokeshire, the contribution they make to the local economy, the many non-directly employed people and companies that they influence and the incalculable and positive effect their community involvement has had over the years.

“They also have an incredibly highly skilled, loyal and motivated workforce,” said Mrs Burns.

The GMB Union, which represents a large number of staff at the site, is urging Chevron to commit itself to Pembroke and not abandon the area, where it is a major player in terms of employment.

GMB organiser Jeff Beck added: “Chevron has a far wider reach in the community and the businesses involved in an area that can ill afford to lose jobs. This is the only plant that Chevron has in Europe and to cut this arm off will be a mistake in terms of short term profitability.”

Preseli Pembrokeshire MP Stephen Crabb said he was deeply concerned about the possibility of major job losses but following talks with Chevron, he is optimistic that the Pembroke refinery will survive.

“There is no question that oil refining in the UK is currently facing a very challenging commercial environment, but I came away from the meeting with Chevron optimistic that the scale and efficiency achieved at its Pembroke site means that it is well-placed to weather the current storm affecting the industry,” added Mr Crabb.