A congressional watchdog is investigating reports that some recipients of a tax credit for clean coal production increased rather than cut pollution, Reuters first reported Monday.

The multibillion-dollar subsidy has gone to numerous major firms over the years, including financial institutions like JPMorgan Chase and Goldman Sachs Group, drugmaker Mylan, and DTE Energy Co, the main utility for Detroit, according to Reuters. The Internal Revenue Service awards the subsidy based on lab results rather than real-world emissions, according to the news service.

The Government Accountability Office (GAO) has launched the investigation following a Reuters investigation indicating some firms awarded the subsidy saw higher levels of pollution. A GAO official confirmed to The Hill that it is investigating the subsidy based on a congressional request.

A 2018 Reuters special report found that Duke Energy, another recipient of the tax credit, produced nitrogen oxide emission rates between 33 percent and 76 percent higher at a North Carolina facility from 2012 to 2014, the first three years it received the subsidy.

The environmental nonprofit Resources for the Future separately released a report in March 2020 indicating the tax subsidy resulted in some coal plants being retired more slowly, meaning more overall carbon dioxide emissions. Those increased emissions, they wrote, exceeded the benefits of reduced nitrogen oxide and mercury emissions.

Congress is set to vote on whether to reauthorize the tax credit at the end of 2021, when it is set to expire, and the outcome of the probe could play a major role in determining its fate.

Sens. Sheldon WhitehouseSheldon WhitehouseA year later, lawmakers long for hugs and Chuck E. CheeseRubio and bipartisan group of senators push to make daylight saving time permanentFeds looking at communications between lawmakers, Capitol rioters: reportMORE (D-R.I.), Elizabeth WarrenElizabeth WarrenPoll: Majority say wealth tax is part of the solution to wealth inequalityThe Hill’s Morning Report – Presented by the National Shooting Sports Foundation – House passes relief bill; Biden set for prime time addressCongressional Hispanic Caucus’s political arm taps new executive directorMORE (D-Mass.) and Sherrod BrownSherrod Campbell BrownGeraldo Rivera won’t run for Ohio Senate seatOn The Money: House passes COVID-19 relief bill in partisan vote | Biden to sign Friday | Senate confirms Fudge to lead HUDSenate panel advances Biden’s picks to lead SEC, consumer bureauMORE (D-Ohio), in a 2019 letter directed to the Internal Revenue Service responding to the reports, called for a re-evaluation of how the tax credit is awarded.

We have evidence to show that Wall Street is raking in hundreds of millions in tax credits each year for pollution reductions they arent coming close to delivering in the real world. Thats a massive boondoggle for taxpayers, a blow to air quality and Americans health, and a setback for our climate, Whitehouse said in releasing the letter.