NEW YORK, March 16 (Reuters) - More than 20 U.S. senators pressed President Donald Trump on Thursday to reject requests from oil refiners to overhaul the U.S. biofuels program, weighing in on a debate that has roiled markets from soybeans to gasoline in recent weeks.
Oil refiners have requested that the U.S. government change the program to push the burden of meeting annual biofuels use requirements downstream, a move that has been met with criticism and backlash from ethanol producers, fuel retailers and others.
The change would be "unwarranted and indefensible," said the bipartisan group of senators that included Charles Grassley from Iowa and Amy Klobuchar from Minnesota in a letter to Trump.
The White House said last week it was considering the changes, whose supporters include billionaire investor and special advisor on regulations Carl Icahn. Icahn is a majority stakeholder in oil refiner CVR Energy Inc.
The news shook the market for biofuels compliance credits and whipsawed some grain prices as traders fretted over how to position ahead of any changes.
The U.S. Environmental Protection Agency under former President Barack Obama in November proposed denying the requests from refiners, but opened the issue up for public comment.
"This type of change would not only wholly undermine the intent of the program, but would also result in a massive, costly, time-consuming shift in compliance," the letter dated March 16 said.
The U.S. Renewable Fuel Standard, signed into law by former President George W. Bush, was designed to boost use of biofuels like ethanol and biodiesel in gasoline and diesel in a bid to curb greenhouse gas emissions, boost rural economies and reduce dependence on foreign oil.
The program has been stymied by regulatory delays and become a battleground between the oil and corn industries in Washington.
Reporting by Chris Prentice; Editing by Richard Chang