Donald Trump has shown little interest in removing the steel and aluminium tariffs he imposed more than a year ago despite growing evidence Americans are paying a hefty price for these tariffs and increasing pressure from Republicans in Congress to remove them.

US consumers and businesses are paying more than $900,000 (£690,750) a year for every job saved or created by Mr Trump steel tariffs, according to calculations by experts at the Peterson Institute for International Economics.

The cost is more than 13 times the typical salary of a steelworker, according to Labour Department data, and it is similar to other economists' estimates that Mr Trump's tariffs on washing machines are costing consumers $815,000 per job created.

"It's very high. It's arresting," said Gary Hufbauer, a senior fellow at the Peterson Institute who did the steel tariff cost calculation. "The reason it's so high is that steel is a very capital intensive industry. There are not many workers."

Mr Trump has said repeatedly that the metals tariffs are necessary for national security, for good-paying jobs and for leverage in trade negotiations.

The Democrat challengers to Trump in 2020 Show all 25 1 /25 The Democrat challengers to Trump in 2020 The Democrat challengers to Trump in 2020 Bernie Sanders The Vermont senator has launched a second bid for president after losing out to Hilary Clinton in the 2016 Democratic primaries. He is running on a similar platform of democratic socialist reform Getty The Democrat challengers to Trump in 2020 Joe Biden The former vice president recently faced scrutiny for inappropriate touching of women, but was thought to deal with the criticism well and has since maintained a front runner status in national polling EPA The Democrat challengers to Trump in 2020 Elizabeth Warren The Massachusetts senator is a progressive Democrat, and a major supporter of regulating Wall Street Reuters The Democrat challengers to Trump in 2020 Amy Klobuchar Klobuchar is a Minnesota senator who earned praise for her contribution to the Brett Kavanaugh hearings Getty The Democrat challengers to Trump in 2020 Michael Bloomberg Michael Bloomberg, a late addition to the 2020 race, announced his candidacy after months of speculation in November. He has launched a massive ad-buying campaign and issued an apology for the controversial "stop and frisk" programme that adversely impacted minority communities in New York City when he was mayor Getty Images The Democrat challengers to Trump in 2020 Tulsi Gabbard The Hawaii congresswoman announced her candidacy in January, but has faced tough questions on her past comments on LGBT+ rights and her stance on Syrian President Bashar al-Assad Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Pete Buttigieg The centrist Indiana mayor and war veteran would be the first openly LGBT+ president in American history Getty The Democrat challengers to Trump in 2020 DROPPED OUT: Deval Patrick The former Massachusetts governor launched a late 2020 candidacy and received very little reception. 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There was hope among Republicans and business leaders that Mr Trump would remove the tariffs - at least on Canada and Mexico - once the US-Mexico-Canada trade agreement negotiations were done. But the tariffs remain, a warning sign for Chinese leaders who want Mr Trump to remove his tariffs on their country's products as part of the deal the two sides are currently negotiating.

Supporters of Mr Trump's tariffs, such as the Alliance for American Manufacturing, counter that more than 12,700 good-paying jobs have been created or saved at steel and aluminium factories since the president put this policy in place in March 2018.

They also point to substantial amounts of investment in US metal mills that should benefit the nation for years to come, including $1bn that was just announced at a US Steel plant outside Pittsburgh.

"Congrats to @U_S_Steel for investing $1+ BILLION in America's most INNOVATIVE steel mill. 232 Tariffs make Pennsylvania and USA more prosperous/secure by bringing Steel and Aluminum industries BACK. Tariffs are working. Pittsburgh is again The Steel City. USA economy is BOOMING!" Mr Trump tweeted last week.

Many economists and business leaders point out that jobs in steel-using industries outnumber those in steel production by about 80 to 1, according to experts at Harvard University and the University of California, Davis.

Mr Trump has claimed other countries are paying the tariff bill, but evidence shows the tariffs are taxes paid by Americans.

US companies that buy metals are either absorbing higher costs or passing them along to consumers. General Motors and Ford said Mr Trump's tariffs have cost them a billion dollars each.

"The consumer pays for this in the end. They just don't always recognise it," said James Knott Jr, chief executive of Riverdale Mills Corporation in Northbridge, Massachusetts, which makes wire mesh products for everything from fences to commercial fishing nets. "These 232 tariffs protect my foreign competition rather than protecting me."

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Raw steel prices surged after Mr Trump put 25 per cent tariffs on imported steel on some countries in March and then expanded the tariffs to most countries in June, including Canada, Mexico and the European Union.

The result is that domestic steel prices have been higher than foreign ones, boosting profits for US steel mills but putting US manufacturers that use steel like Riverdale at a disadvantage to European and Chinese competitors.

Riverdale is absorbing the tariff costs for now, but Mr Knott Jr said it forced him to cut costs elsewhere. He ended up reducing his 200-person workforce by 50 people. He did it via attrition - simply not filling vacancies after people left - but it is hampering him at a time when he says business should be thriving in a strong economy.

Republicans in Congress are growing increasingly vocal in their insistence that Mr Trump remove the steel and aluminium tariffs, at least on Canada and Mexico, which are major feeders of metals to the United States. Some GOP senators are threatening not to approve Mr Trump's USMCA agreement until the tariffs on US neighbours are removed.

"If these tariffs aren't lifted, USMCA is dead. There is no appetite in Congress to debate USMCA with these tariffs in place," wrote senator Chuck Grassley, R-Iowa, last week in a Wall Street Journal opinion piece.

Tom Gibson, president of the American Iron and Steel Institute, said Mr Trump's tariffs are about righting years of foreign nations like China undercutting US steel production. He points out that US steel mills are now running at more than 80 per cent capacity, a level not seen in over a decade and that imports have fallen from 29 per cent a year ago to 20 per cent now.

"The steel tariffs implemented by the president last year have enabled steelmakers to begin to recover from the historic import surges that devastated the industry a few years ago," Mr Gibson said. "The tariffs are working, but now is not the time to lift them."

But evidence is growing that the metals tariffs are starting to bite. Last year, US manufacturing companies went on a hiring spree, adding the most new employees in more than two decades as the good economy caused demand to rise. But since the start of the year, manufacturing job growth has cooled.

From February to April, US manufacturers added 12,000 net new manufacturing jobs, the weakest gains in the sector since before Mr Trump took office.

Mr Hufbauer and Euijin Jung of the Peterson Institute calculated that every steel job saved is costing US consumers over $900,000 because US companies have been paying about 10 per cent more for steel since Mr Trump's tariffs went into effect. The total additional cost to the economy is about $11.5bn a year.

There is debate among economists about how many jobs have truly been created or saved because of Mr Trump's tariffs, but Mr Hufbauer and Mr Jung decided to take the Alliance for American Manufacturing's figure for 12,700, which works out to over $900,000 a job.

AAM said about 9,300 of those jobs are steel alone, which means the cost could be more than $1.2m per steel job.

Supporters of tariffs counter that the US Treasury is receiving some revenue from the tariffs and that the longer the tariffs remain in place the more the domestic industry will thrive.