WASHINGTON, June 30 (Reuters) - Coal used to make steel got a break in the latest version of President Donald Trump's tax bill, a subsidy that could be worth hundreds of millions of dollars over 10 years for a fuel that is mostly exported to countries including China.

In April, Trump signed executive orders that directed Chris Wright, the energy secretary and former fracking CEO, to determine whether metallurgical, or met, coal is a "critical mineral" which he did in May.

In the latest version of Trump's so-called One Big Beautiful Bill that the Senate released over the weekend, met coal can claim an advanced manufacturing production tax credit, available for critical minerals, that would pay 2.5% of costs for the fuel.

Sonia Aggarwal, CEO of Energy Innovation, a non-profit group, called allowing met coal to get the credit insane, as it could harm efforts to move to fuels that are less carbon-intensive.

The subsidy would "send hundreds of millions of taxpayer dollars to China to subsidize dirty steel," Aggarwal said in a post on X. Robbie Orvis, a director of analysis at Energy Innovation, estimated that the credit could be worth $300 million to met coal producers sending coal to China over ten years and said the subsidy could help China compete with U.S.-made steel.

Giving met coal the critical mineral classification, typically reserved for minerals needed for high-tech defense systems, could also set the table for Trump's use of emergency powers to raise production.

Conor Bernstein, a spokesperson for the National Mining Association, said the bill supports U.S. jobs, manufacturing and the economy. "Providing incentives to spur steel-making coal production accomplishes each of those objectives."

The Metallurgical Coal Producers Association of West Virginia did not immediately respond to requests for comment about how the tax credit would benefit producers.

West Virginia, one of the top U.S. mining states, has suffered several met coal layoffs in recent months hitting hundreds of miners. In local media, Ben Beakes, the president of the West Virginia met coal association, has blamed the layoffs on inflation.