Several hundred members of the United Steelworkers (USW) operate U.S. Steel’s Irvin Plant, producing flat-rolled sheet for the GE refrigerators, ovens and other appliances that keep American households running.

USW members at other U.S. Steel locations across the country make tin for food cans, pipe for natural gas distribution systems and steel components for bridges, along with many other products for critical infrastructure and national security.

Only domestic control of steelmaking facilities will ensure a ready supply of these essentials for everyday use and in times of crisis. Unfortunately, the proposed sale of U.S. Steel to a Japanese company, Nippon Steel Corp., puts this security at risk.

With an annual domestic production capacity of 17.4 million net tons, U.S. Steel is one of America’s most important steelmakers, a linchpin of numerous supply chains and industries that keep families safe and the nation moving.

While many Americans worked remotely during the pandemic, for example, USW members continued operating U.S. Steel’s facilities to help supply the goods pivotal to the covid-19 economy and the nation’s safety.

This isn’t new. As Pittsburghers know, union workers at U.S. Steel always step up when the nation needs them most.

But the proposed sale of U.S. Steel to Nippon Steel Corp. through one of its shell companies, Nippon Steel North America, throws the future into question.

A foreign owner might attempt to divert U.S Steel’s products for its own country’s use during the next crisis, leaving America shorthanded.

Or it could close plants altogether. America cannot risk ending up like the United Kingdom, where an Indian company dominating the steel industry recently announced closings and layoffs posing grave threats to the UK’s economy and security.

It isn’t just the future of U.S. Steel’s mills that is at stake. A foreign owner could transfer U.S. Steel’s intellectual property out of the country or simply starve domestic research and development, hindering America’s future production of items like electrical steel for electric vehicles or tubular products for clean energy projects.

And these are just a few of the reasons making Nippon an unfit owner for U.S. Steel.

While America and Japan are political allies, they’re also economic competitors. Japan has a history of dumping cheaply priced goods in U.S. markets, killing jobs across numerous industries.

In 2018, for example, the USW successfully pushed for Section 232 tariffs on steel and aluminum from several countries threatening our security, including Japan. These duties came on top of other tariffs previously placed on unfairly traded Japanese steel.

Worse, foreign ownership of critical industries has the potential to stymie future enforcement of trade laws and thwart American workers’ fight for a level playing field.

U.S. Steel often joined the USW in pursuing penalties on trade cheaters. But it is doubtful that kind of cooperation would continue with Nippon’s bosses in Tokyo making decisions based on global political considerations and far-flung financial holdings, including business interests in China.

The USW has stressed these risks to the Biden administration, which agrees that the proposed deal requires “serious scrutiny.”Members of Congress from both parties also stepped forward to oppose the sale.

USW members will continue to fight the deal with Nippon. They refuse to jeopardize America’s security or sit by while U.S. Steel’s shareholders attempt to line their pockets at the price of America’s safety.

Union workers built this country. And we’ll always step forward to defend it.

David McCall is the international president of the United Steelworkers (USW).