Jan 12 (Reuters) - The Biden administration is considering lowering the 2022 ethanol blending mandate below the proposed 15 billion gallons amid backlash from the refining lobby and unions arguing the nation's shrinking ethanol industry can no longer support the target, according to two sources familiar with the administration’s thinking.

U.S. President Joe Biden vowed to bring some normalcy back to laws requiring refiners to blend biofuels like ethanol into the nation’s gasoline pool after his predecessor, Donald Trump, took unprecedented steps to relieve refiners from the requirement.

But Biden is finding it difficult to live up to his promise. The COVID pandemic has dampened fuel consumption and triggered a handful of ethanol plant shutdowns. Higher regulatory costs have refiners threatening to close refineries and shed high-paying union jobs.

In December, the Environmental Protection Agency issued a long-awaited biofuel blending mandate proposal that cut ethanol requirements for 2020 and 2021 but restored them to 15 billion gallons for 2022. Farmers and biofuel producers criticized the rollbacks but welcomed the restoration this year.

But, in recent weeks, administration officials have considered rolling back the 15 billion gallon mandate when the final rule is issued later this year, the two sources told Reuters. (Reporting By Jarrett Renshaw and Stephanie Kelly, Editing by Chizu Nomiyama)