Every investment comes with a bit of risk.

Still, the global chemical giant DuPont must have found it a bit galling that an investment of hundreds of millions of dollars might fall victim to a wavering federal commitment.

So it seemed from testimony last week by senior vice president James C. Collins Jr. before the Senate's Committee on Environment and Public Works.

"I hope you agree that DuPont and other businesses investing in a policy set forth by Congress should not have the rule changed midcourse," Collins told the committee.

The Environmental Protection Agency was proposing just such a "midcourse" change for the Renewable Fuel Standard (RFS), which is a federal program launched in 2005 as a way of reducing the nation's reliance on foreign oil.

The RFS set a rising standard for how much of the nation's fuel supply must be made up of renewable nonpetroleum sources, such as corn ethanol and ethanol produced from plant and animal waste.

The RFS has called for up to 36 billon gallons of renewable fuel to be blended into the nation's fuel supply by 2022. The figure was set at 18 billion gallons for 2014.

The standards set in motion an expansion of the nation's biofuel industry.

DuPont is building a $200 million plant in Nevada, Iowa, that will produce 30 million gallons of fuel from the remains of corn plants once the corn is harvested. It also has partnered with BP to create and market technology to produce butanol, an alternate fuel with more energy content than ethanol.

Those efforts would be undercut, Collins testified Wednesday, by the EPA's recent proposal to lower the 2014 standard for renewable fuel to 15 billion gallons.

The EPA says the reduction is needed because, as gasoline consumption has declined, the overall percentage of ethanol in the fuel supply is approaching 10 percent, beyond which the blend becomes more corrosive to older cars and fuel infrastructures.

The EPA's plan was cheered by oil companies and food producers, such as chicken farmers, who complain that biofuel industry has driven up feed costs as more corn was diverted to make ethanol.

Speaking for DuPont, Collins said the reversal would be bad for the nation and his company.

"Reversing course on the RFS would deny the country a true alternative fuel," he said. "Without the RFS, America can be all but certain that investment in advanced renewable fuels . . . will halt for at least a generation.

". . . DuPont has invested considerable capital and is on track to meet the demands of the RFS. Changes in renewable-fuels policy may put those investments at considerable risk."

The EPA will take public comment on the proposed change until the end of January.