UPDATE 1-U.S. biofuel credit prices fall as EPA considers change

(Adds potential changes to renewable fuel program)

NEW YORK, Sept 28 (Reuters) - Prices for U.S. renewable fuel credits fell on Thursday, traders said, because of a Environmental Protection Agency proposal that would significantly increase the amount of credits on the market.

The most popular fuel credits, known as D6, fell to 66 cents in early trading on Thursday, a 15-cent drop since Wednesday and the lowest price since May, traders said.

The EPA is considering a change to U.S. biofuels policy that would allow exports of ethanol to count toward the country's annual biofuels volumes mandates, Reuters reported Wednesday.

The addition of the credits would lower prices and costs for merchant refiners. Under the program, refiners must either blend the renewable fuels into the fuel pool or buy credits from those who do.

Earlier in the week, the EPA it was considering cutting how much advanced biofuel and biodiesel must be mixed into the American fuel supply in 2018 and 2019, based on a potential spike in biodiesel prices.

The EPA's efforts will face significant opposition from the powerful corn lobby and from lawmakers from agricultural states like Iowa, Illinois and Nebraska. (Reporting By Jarrett Renshaw; Editing by Bernadette Baum and Marguerita Choy)