The tariff will no longer apply to rolled metal exports from the EU thanks to a deal struck between Washington and Brussels that would have applied to the UK if it had not withdrawn from the bloc.
EU companies will also be able to export aluminum duty-free.
UK Foreign Trade Secretary Anne-Marie Trevelyan tried but failed to get the same deal during her visit to the United States. The Guardian newspaper said it hopes to talk about the topic again when the US Secretary of Commerce visits London in January.
Gareth Stays, CEO of UK Steel, told The Guardian: “UK steel exports to the US have halved since President Trump imposed steel tariffs in 2018. There is no doubt that these measures have seriously damaged the interests of Great Britain in the second - the largest export market for steel. ”
Donald Trump imposed tariffs for so-called national security reasons, arguing that imports undermine the US's ability to produce its own steel. President Joe Biden has since failed to repeal a highly controversial law.
The US-EU tariff cut agreement could also affect UK steel exports to Europe, as it includes a clause that calls for tariffs to be applied to EU products, including recycled UK steel.
The UK steel industry has called on the government to offer government assistance to help it overcome the crisis.
Stace said: "It is very important that the government does its utmost to secure the deal and ensure that British steelmakers can sell their steel to the United States."
Business Matters magazine quoted Unite's Harish Patel as saying the government should explain why the EU was able to strike a deal while the UK failed.
“The government needs to sort this out quickly,” he said. "If tariffs are not quickly removed, hundreds of jobs in the steel and related industries ... will be at risk."
The UK government insisted that Washington's apparent disdain was not tied to London's threats to re-establish a hard border with the island of Ireland, which would fuel sectarian violence and anger the United States.
And the government of Prime Minister Boris Johnson has said it is ready to retaliate with sanctions on US exports to the UK if the need arises.
Steel has been an important part of the UK economy for over 200 years and has been the engine of the industrial revolution.
With more steel produced in the first half of the 19th century than any other country, Britain has steadily declined in rankings.
Thanks to automation and declining competitiveness, the number of people working in this sector has dropped from 197,000 in 1974 to about 18,000 today.
