In an interview on Thursday, Mr. Schumer said he was frustrated that a process the president began this spring as a precursor to imposing tariffs had not culminated in any action and had actually made things worse for United States companies.

When the administration announced the investigation, “we felt, O.K., they’ve got the message. But they’ve just dragged their feet and delayed and delayed,” Mr. Schumer said. “The bottom line is the president has been a total paper tiger on this issue, and as a result, we feel the need to hold up nominees for the Commerce Department.”

The delays in imposing the tariffs appear to have further worsened conditions for the American steel industry, which was already struggling financially with a global glut of cheap metal. To get ahead of the tariffs, foreign manufacturers appear to have shipped more steel and aluminum into the country. Steel imports rose 20 percent in the five months since the investigation was announced in April, compared with the previous five months, the American Iron and Steel Institute said on Thursday.

The import surges have helped fuel more layoffs and plant closings, according to Scott Paul, the president of the Alliance for American Manufacturing, which represents steel companies and workers. According to Mr. Paul, that includes layoffs of 180 workers at the Dura-Bond Industries plant in Steelton, Pa., and 150 workers at ArcelorMittal’s rolling mill in Conshohocken, Pa.

The president signed executive orders in April calling for the Department of Commerce to open two separate investigations into whether imports of steel and aluminum were harming American national security. Initiated under the rarely used Section 232 of a 1962 trade law, the investigations gave the president broad authority to impose tariffs or other restrictions on imports. Proponents of such measures said a glut of Chinese metal was depressing worldwide prices to such low levels that American manufacturers could not remain in business.