Seven Democratic U.S. senators have launched an investigation into a $370 million "alternative fuel" tax credit payout that Cheniere Energy received from the IRS earlier this year. Critics argue the liquefied natural gas export company was not eligible for the credits.

The investigation centers on whether LNG exports should qualify for tax incentives designed to promote cleaner alternative fuels. Natural gas, while cleaner-burning than coal, still produces significant carbon emissions and contributes to climate change when exported as LNG.