FARGO, N.D. — U.S. Sen. Heidi Heitkamp, D-N.D., flanked by five other Democratic senators, and producer/processors from their states, launched an effort Wednesday to re-up federal support for biofuels.

Heitkamp emceed a conference call and phone press conference in Washington, involving Sens. Amy Klobuchar and Al Franken of Minnesota, as well as Dick Durbin of Illinois, Maria Cantwell, Washington and Joe Donnelly, Indiana, and producers or processors from several states.

The six senators said they are opposing a U.S. Environmental Protection Agency proposed rule to cut the required amount of biofuels to be produced in the U.S.

The proposed RFS rule would reduce the conventional corn-based ethanol target to 13 billion gallons, according to a press release from Klobuchar. This is 800 million gallons below the 2013 target of 13.8 billion gallons, and 1.4 billion gallons below the 2014 statutory target of 14.4 billion gallons.

The rule sets the advanced biofuels, which includes biodiesel, target at 1.28 billion gallons, while the industry is currently producing about 1.8 billion gallons.

They are asking Congress to extend the biodiesel tax credit, which ended Dec. 31, 2013. Cantwell is a co-sponsor of S. 2021, the Biodiesel Tax Incentive Reform and Extension Act of 2014, which would extend a $1 per gallon tax credit for biodiesel producers through 2017.

Heitkamp said the EPA rule and the proposed cutback in the nation’s Renewable Fuel Standard have created uncertainty and prompted the industry to pull back on production. She cited a National Biofuels Board survey that indicates 80 percent of biodiesel producers have cut production. Almost six in 10 have stopped production. Two-thirds will cut their workforce. About 85 percent have delayed or cancelled expansion. She said the proposed cutback would hurt plants including the ADM biodiesel plant in Velva, N.D. Heitkamp and others have been urging EPA Administrator Gina McCarthy to change her mind.

Among others from around the country, Terry Goerger, a Mantador, N.D., farmer and biofuels proponent, said the federal changes cause uncertainty for the 80 workers at ADM in Velva. “Uncertainty is bad for agriculture,” Goerger said, adding that investors have taken cues from Congress and the administration to build plants and now they are “pulling the rug out from under us.”

Klobuchar said biofuels account for 10 percent of the U.S. fuel market and — along with oil fracking in places like North Dakota, and more fuel-efficient vehicles — has reduced U.S. dependence on foreign energy from 60 percent to 40 percent of use. She called on the administration to “abandon its efforts to weaken the RFS and focus on creating a stable, predictable environment that will help our biodiesel producers create jobs and power our economy.” Franken credited biofuels with cutting dependence on foreign oil. Both cited Minnesota Department of Agriculture statistics that the change in the RFS would cost 1,500 jobs and $600 million in annual economic activity.

Franken said biofuels have other advantages: “You’re never going to see a biodiesel spill in the Gulf of Mexico,” he says.

The senators said the RFS would establish a biofuel standard of 1.28 billion gallons this year. Last year, biodiesel producers — using products like soybeans and canola — generated a record 1.8 billion gallons and supported 62,200 jobs. Greenhouse gas emissions from biodiesel are 57 percent to 86 percent less than from petroleum diesel.