WASHINGTON — More biodiesel, please. That’s the message from 36 senators to the U.S. Environmental Protection Agency (EPA) as the public comment period for the agency’s proposed changes for biofuel volumes in the Renewable Fuel Standard (RFS) draws to a close.

Led by Sens. Chuck Grassley (R-Iowa), Patty Murray (D-Wash.), Roy Blunt (R-Mo.) and Heidi Heitkamp (D-N.D.), a bipartisan group of 36 senators wrote to EPA administrator Gina McCarthy to urge the EPA to boost its proposed Renewable Volume Obligations (RVO) for biodiesel production under the RFS (click here to view the letter).

After a long delay, the EPA announced in May its proposed biofuel RVOs for 2014, 2015 and 2016. For biodiesel, the proposal calls for the 2014 RVO to match the actual usage last year, or 1.63 billion gallons. The proposal calls for increasing the RVO to 1.7 billion gallons for 2015 and then by an additional 100 million gallons for each following year to hit 1.9 billion gallons in 2017.

But these increases, the senators argue, do not reflect the biodiesel industry’s production capabilities. The National Biodiesel Board, a biodiesel industry trade group, has called for an RVO of 2.7 billion gallons by 2017.

“While the proposal is a positive step for biodiesel, we remain concerned that the proposed biodiesel volumes for 2016 and 2017 fail to adequately recognize the domestic biodiesel industry’s production capacity and its ability to increase production,” the letter states.

“Biodiesel is the first EPA-designated advanced biofuel under the RFS to reach commercial-scale production nationwide,” it continues. “It is exceeding the goals that Congress envisioned when it created the RFS with bipartisan support in 2005, while creating jobs, generating tax revenues, reducing pollution, and improving energy security. We urge you to support continued growth in the domestic biodiesel industry by making reasonable and sustainable increases in the biodiesel volumes for 2016 and 2017 in the final rule.”

The EPA’s delay in setting RVOs for biodiesel created great uncertainty for domestic producers and their employees, the letter notes, crimping production and even leading to some plant shutdowns, layoffs and lost economic productivity. According to the NBB, nearly every state produces biodiesel, and the industry supports more than 62,000 jobs.

The senators’ letter further cites EPA’s decision earlier in 2015 to consider imports from Argentinean biofuel producers under the RFS. The senators argue that these additional imported volumes must be considered in the final biodiesel volumes to prevent displacing domestic production.

EPA will finalize the RVOs for 2014 through 2017 by Nov. 30, 2015.