WASHINGTON, April 7 (Reuters) - A group of Democratic

U.S. senators on Tuesday pressed Treasury Secretary Scott

Bessent on whether enormous tankers that ship liquefied natural

gas qualify for a lucrative tax credit meant for smaller boats

that burn the fuel.

Here are details about the issue.

* The Alternative Fuel Excise Tax credit, signed by former

President George W. Bush in 2005, was meant to decrease oil

dependence by subsidizing a transition among smaller motorboats

to alternative fuels, such as natural gas, propane and LNG.

* Burning the fuel in LNG tankers does not help transition

off liquid fuels such as bunker fuels, critics say, because many

LNG tankers are already designed to burn LNG that boils off

during shipping. That boiled-off gas otherwise would be vented

to the atmosphere or chilled back into LNG.

* "Providing tankers with AFET credits would unnecessarily

waste taxpayer money while doing nothing to protect the

environment, reduce costs for everyday Americans, or lessen the

United States' dependence on oil," the senators said in the

letter. Senators Jeff Merkley, Elizabeth Warren and Chuck

Schumer and four others signed the letter.

* The AFET credit was meant for motorboats, the senators

said, which some federal regulations define as less than 65 feet

long (20 metres) - tiny compared to LNG tankers, which can

measure about three football fields long.

* Cheniere Energy disclosed in February that it got

a $370 million tax break for burning the fuel in its LNG

tankers. Cheniere said it had no comment.

* The Treasury Department did not immediately comment.

* Senate Democrats have limited power now because they are

in the minority, but that could change after the November

midterm elections.