The threatened plant has provided Amlwch jobs for more than 50 years
A US chemical plant in Anglesey has been offered £1.8m to stay open by the Welsh Assembly Government - or alternatively told to repay more than £750,000 in grants it has already had.
Up to 100 chemical jobs are in the balance after giant Great Lakes Chemical Corporation announced last month it may be forced to shut its Amlwch plant.
The company says the Welsh operation is not profitable.
Assembly Economic Minister Andrew Davies outlined the offer of additional Regional Selective Assistance money available to keep the firm in Wales in a letter to Great Lakes' executive vice president.
Mr Davies said he had heard of the plant's proposed closure "with great disappointment ".
With the investment in the plant by Great Lakes over the past few years which included "significant support" from the Welsh Assembly Government, Mr Davies said he had hoped that the facility would operate well into the future.
"There is, of course, an Assembly Regional Selective Assistance grant still available to your company to help develop and upgrade the facility at Amlwch of which £1.82 million could be claimed on further investment.
"On the other hand with closure we will have no choice but to recover the £772,000 already paid," he said.
The Amlwch plant's site manager Brian Macconnachie told BBC News Online the company had not yet received an officially signed copy of the letter:
"It would be inappropriate to comment but as a responsible company we will taking the matter seriously.
He did not rule out the plant, formerly known as the Octel works, and its jobs could still be saved.
Mr Macconnachie said in October the plant was under threat because it "remains uncompetitive."
Great Lakes Chemical Corporation is one of the world's leading producers of certain speciality chemicals for applications like water treatment, speciality household cleaners and performance chemicals.