Detroit three largest automakers will shut down their U.S. plants to stop the spread of coronavirus, bowing to pressure from the union representing about 150,000 hourly workers at those facilities, industry officials said.

Ford Motor Co. and General Motors Co. confirmed the decisions to shut U.S. plants, as well as factories in Canada and Mexico. Fiat Chrysler Automobiles NV was expected to follow suit.

The Detroit automakers’ shares took a beating on Wednesday, with GM (NYSE: GM) falling more than 25% at one point. Ford (NYSE: F) fell as much as 17% and Fiat Chrysler (NYSE: FCAU) sank 16%. The Detroit automakers’ North American factories build their most profitable trucks and sport utility vehicles, such as Fiat Chrysler’s Jeep Wrangler, GM’s Chevrolet Silverado pickup and the Ford F-series truck line.

The actions come less than a day after the automakers and the United Auto Workers union agreed to keep plants running with reduced shifts and staffing, and more time allowed for cleaning.

But that deal was put aside on Wednesday morning after Honda Motor Co. said it would shut its North American factories for six days because of a slump in demand, and a worker at a Ford assembly plant in Michigan tested positive for the coronavirus.

Ford on Wednesday morning closed the final assembly building at its complex in Wayne, Michigan, where it builds the Ranger pickup truck and will assemble Bronco sport utility vehicles.

Ford said it would close all its North American plants after Thursday evening’s shifts through March 30 to thoroughly clean the factories in the United States, Canada and Mexico.

United Auto Workers (UAW) union President Rory Gamble, who had previously called on the automakers to close their U.S. plants, in a Wednesday statement called the shutdowns “the prudent thing to do.”

Ford North American President Kumar Galhotra said the No. 2 U.S. automaker was working closely with union leaders to protect workers. “In these unprecedented times, we’re exploring unique and creative solutions to support our workforce, customers, dealers, suppliers and communities,” he said in the same statement.

“Recent developments in North America make it clear this is the right thing to do now,” GM Chief Executive Mary Barra said in a separate statement.

Meanwhile, other automakers in North America are still operating assembly plants. German automaker BMW said its assembly operation in Spartanburg, South Carolina, was operating, and the company had taken precautions to separate workers. Tables and chairs had been removed from break areas, a spokesman said.

Tesla Inc. was operating its plant in Fremont, California, on Wednesday, despite a statement from local officials that the factory cannot continue to operate as the San Francisco Bay Area began a three-week lockdown.

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