A top ethanol lobbyist was the only House witness on Friday to oppose legislation to revamp the ethanol mandate, and said producers can’t support the bill because there’s too much uncertainty about whether it will lead to more ethanol consumption, or less.

“We can and will continue to support the development and use of high-octane, mid-level ethanol blends for the use in today’s and future vehicles; however, we cannot support what would only be a modest move in octane at the expense of one of the most successful energy programs in the last decade with the RFS,” said Emily Skor, CEO of the trade group Growth Energy.