(AP) — A new Associated Press investigation finds that the push to produce corn-based ethanol has fallen short of clean energy expectations and appears to be causing more environmental damage than promised.

The AP’s investigation is based on government data, interviews and observations. It highlights what many researchers have published in peer-reviewed journals and is consistent with reports by the Environmental Protection Agency.

The investigation finds that farmers rushing to plant more corn wiped out millions of acres of conservation land, destroyed habitat and polluted water supplies with fertilizer use.

The consequences are so severe that environmentalists and many scientists have now rejected corn-based ethanol. The Obama administration stands by its policy.

Ethanol supporters are pushing back hard at the AP report, calling it a “smear.”

Congress is working to do away with requirements that oil companies blend ethanol into their gasoline, something Big Oil is supporting.