WINDSOR, Ontario — Since 1988, the hulking presses at Lanex Manufacturing on the edge of Windsor, Ontario, have been stamping out door strikers, folding-seat latches, tailpipe hangers, frame braces and other prosaic bits of metal that make their way into vehicles ranging from Corvettes to Honda minivans.

But, these days, worries about the future permeate the plant as President-elect Donald Trump prepares to enter the White House. He has threatened to impose a 25% tariff on all goods exported from Canada to the United States. In Windsor, that would ravage its lifeblood: automobiles and everything that goes into them.

“Everybody’s waiting for the next shoe to drop,” Bruce Lane, president of Lanex, said in its boardroom, whose walls were made of painted concrete blocks. “If Windsor lost its automotive business, Windsor would not survive.”

Few Canadian cities are as acutely aware as Windsor of the integration of the two countries’ economies. The city sits just across the Detroit River from Detroit, and Canada’s maple-leaf flag often flies next to the stars and stripes there. And no industry has been interwoven across the border for as long as automaking.

“These workers here in Windsor are more exposed to trade with the United States than anyone else,” Prime Minister Justin Trudeau said at a steel plant during a recent visit to the city.

Trump, he added, “is proposing tariffs that would damage not just people here in Windsor but people right across the country and indeed in the United States.”

Windsor’s two major landmarks are shared with Detroit: the $5.7 billion Gordie Howe International Bridge, scheduled to open this year, and the 96-year-old Ambassador Bridge, which carries about $300 million in cross-border trade each day. Of Canada’s $440 billion in annual exports to the United States, only oil and gas generate a larger amount than cars, trucks and auto parts.

But with Canadian officials taking Trump at his word that he will follow through on his threat of tariffs, Lane and others in the auto industry are bracing for the potential fallout.

George Papp is CEO of Papp Plastics, whose headquarters sits near the imposing new suspension bridge. He said his U.S. customers, mainly automakers, would simply invoke the terms of contracts he has with them and deduct the cost of tariffs from the amount they pay him.