General Motors says it has rejected various proposals by Unifor to keep the Oshawa assembly plant open past 2019.

The company, which met with Unifor president Jerry Dias today on the future of the plant, says the options suggested by the union would mean substantial incremental cost increases and hurt the company’s competitive position.

The union had proposed several options to extend production at the plant including extending the life of vehicles currently produced there, and shifting production planned for Mexico to Oshawa. GM says it has instead asked Unifor to work with the company on transition support for the close to 3,000 Oshawa assembly workers who will lose their jobs when the plant shuts.