A major steelworkers union has moved a step closer to striking, voting to authorize a labor stoppage that, if carried out, could derail the industry’s growth at a time when President Trump has touted its resurgence.

About 15,000 workers at plants owned by ArcelorMittal have unanimously voted to give the committee bargaining for new contracts here the right to call a strike within two days’ notice, union officials announced Monday. That followed a similarly unanimous vote to authorize a strike from about 16,000 workers of U.S. Steel.

Together, the two companies account for nearly 25 percent of U.S. steel production, and a strike could hold back the industry at a time when it is benefiting from federal intervention aimed at boosting production and employment.

The Trump administration has imposed tariffs on imported steel and aluminum, aiming to protect domestic producers from foreign competition. U.S. steel profits have surged over the last two years despite a downturn in 2015 and 2016, as prices fell in part because of an international oversupply coming from China, according to Phil Gibbs, a steel analyst at KeyBanc Capital Markets. The industry has rebounded in 2017 and 2018, in part because of the tariffs, with the prices of hot-rolled coil — a key metric of steel prices — experiencing an increase of about 30 percent.

Unions negotiating new contracts argue that their members deserve a bigger share of the benefits.

They were already aggrieved over what they call stagnant wages, proposed increases to their health-care costs, changes to overtime rules and other issues. Officials involved in bargaining said that recent negotiations have not gone well and that the sides remain far apart on significant matters, most notably on the proposed additional cost-sharing for workers’ health-care plans.