In an October 19 letter to corn-belt lawmakers, Environmental Protection Agency (EPA) Administrator Scott Pruitt said that he won’t seek any rollback to biofuel blending rules, according to Reuters.

The agency had been considering some changes to rules set by the Obama administration that ratchet up the amount of renewable biofuel that refineries must blend into the gas and diesel they sell. According to Bloomberg , the EPA had specifically been considering “a possible reduction in biodiesel requirements” as well as “a proposal to allow exported renewable fuel to count toward domestic quotas.” In early October, the EPA asked for public comment on cutting biodiesel quotas.

The Bloomberg story cited unnamed sources who said President Trump personally directed Pruitt to back off any proposals that would relax biofuel quotas after pressure from lawmakers from corn-producing states like Iowa, Nebraska, and Illinois. Trump, who courted both fossil fuel interests and corn-belt states in his campaign, has had pressure from each side on this debate. Uncertainty surrounding the future of biofuel use during Trump's administration has caused volatility in biofuels markets for months, Reuters notes.

(The Bloomberg story also cites one unnamed “top EPA official” who said that Trump’s directive to Pruitt didn’t matter because Pruitt wasn’t going to alter renewable fuel standards anyway.)

Regardless, the pressure to solidify plans for biofuel quotas, specifically corn-based ethanol, caused some political turmoil. Earlier this week, Iowa Senator Chuck Grassley threatened to block Trump’s nominees for unfilled posts at the EPA until the EPA backed off proposed changes to Renewable Fuel Standards (RFS), the Des Moines Register wrote on Wednesday.

Pruitt’s Thursday letter to lawmakers appears to be a win for biofuels and a loss for fossil fuel refiners who contend that increasing biofuel blends in fossil fuels is costly for them and degrades the quality of the fuel.

Reuters also noted that Pruitt’s letter offered to work with Congress to allow the sale of E15 gasoline—or gasoline with 15 percent ethanol—year-round. Currently, the sale of E15 gas is restricted in the summer because of concerns about smog. (Today, most gas in the US is 10 percent ethanol or less.) While ethanol is seen as a relatively “green” fuel because plants pull carbon dioxide from the air while they're growing, burning ethanol can release more smog-forming pollution.

In November 2016, just before Trump took office, the Obama administration's EPA increased refinery quotas for mixing cellulosic biofuels, biomass-based diesel, advanced biofuel, and traditional renewable fuel into their fossil fuels.