A U.S. manufacturing group asked President Joe Biden to end tariffs on steel and aluminum imports, setting the stage for a debate on protective trade measures.

The Coalition of American Metal Manufacturers and Users said the tariffs hurt family-owned businesses and fractured relationships with trading partners. A letter from the group asked Biden to end former President Donald Trump’s tariffs and to ask countries to address the issue of excess steel and aluminum capacity in China.

“By taking action to terminate the Trump tariffs, your administration can prevent U.S. manufacturers from shutting down production lines, laying off workers, and potentially even closing their doors,” Paul Nathanson, the executive director of the group, said in the letter dated Wednesday.

“Thousands of manufacturers cannot procure the necessary raw materials in the U.S. in sufficient and reasonably available commercial quantities ––and of a satisfactory quality –– leading American companies to rely on imports,” he said.

Biden said last week he would keep U.S. tariffs on aluminum imports from the United Arab Emirates, a major supplier, reversing a last-minute directive by Trump.

The United Steelworkers, most U.S. steel producers and Century Aluminum Co. have asked Biden to maintain tariffs.

The coalition said it represents more than 30,000 companies and more than 1 million workers.