Massena's General Motors plant will go on permanent idle on January 26, about six months sooner than previously scheduled.
Assemblywoman Addie J. Russell said she was phoned by GM officials with the bad news on Friday.
GM announced last year that it would close the Massena Powertrain facility by the end of 2008. Then in August, the company announced the closure had been delayed until the middle of 2009.
Today's announcement puts the closure plan back on its original track.
GM employees at Massena had been on extended annual layoff since December 19 and had been scheduled to return to work January 26.
Assemblywoman Russell said her sources say about 50 employees may be kept on for an indefinite period beyond Monday.
"I am very concerned about this development, particularly at a time when the national economy is pushing our unemployment numbers to record levels in St. Lawrence County and throughout the North Country," Ms. Russell said.
She said affected workers are invited to call her office at 786-0284 if she can be of any assistance.