A portion of the General Motors Canada transmission plant in St. Catharines, Ontario, will come back online May 11, with most of the rest of its North American manufacturing operations resuming the week of May 18, the automaker said today.

In a statement, GM Canada said “a portion” of its HFV6 engine line would resume on May 11. The 3.6-liter HFV6 engines power the Chevrolet Impala sedan, Chevrolet Colorado pickup, Buick Enclave crossover and GMC Terrain crossover, according to the automaker’s website.

The rest of the St. Catharines plant, as well as the automaker’s CAMI assembly plant in Ingersoll, Ontario, where the Chevrolet Equinox is assembled, and the Oshawa, Ontario, stamping operation will “come back gradually in the weeks that follow,” GM Canada said. It was not immediately clear if they would resume the week of May 18, though the automaker said it planned to resume production at a majority of its North American plants then.

“Based on conversations and collaboration with unions and government officials, GM is targeting to restart the majority of manufacturing operations the week of May 18in the U.S. and Canada under extensive safety measures,” GM Canada said in a statement. “These procedures meet or exceed the World Health Organization and the Public Health Agency of Canada guidelines, and are designed to keep people safe when they arrive, while they work and as they leave the facility.”

Unifor President Jerry Dias said there would be about 300 employees who will begin work at St. Catharines on Monday. He said they would be “strictly volunteers” and that they would pass through “heat cameras” when entering the factory and will receive personal protective equipment.

Dias said he anticipated the CAMI plant coming back online on “more like the 25th” of May, as opposed to May 18, though he stopped short of endorsing a return to work then.

“We’ve got to make sure that our members are comfortable,” he said. “I’m not rushing into any sort of decision here.”

GM was the latest automaker to target a May 18 restart date for most of its North American assembly plants. Fiat Chrysler Automobiles said it was also aiming to resume production that week, though Dias told Automotive News Canada on Tuesday that Unifor was not yet convinced that FCA’s plants would be safe enough by then.

Canadian auto manufacturing has been virtually shut down since mid-March due to the COVID-19 pandemic.