Senator Tom Harkin is accusing the oil industry of underhanded attacks on ethanol, the corn-based fuel additive. Harkin says the Clean Air Act should not be changed to eliminate requirements that ethanol or some other additive be used to make fuel burn cleaner. Harkin says federal regulators have been fooled before by the oil industry, which is touting a new fuel additive Harkin terms a “witches brew.” Harkin says ethanol is the logical additive to replace M-T-B-E, which has contaminated water in California, but the oil companies don’t like ethanol because it’s not petroleum-based.Harkin says by forcing motorists in smoggy cities to use ethanol or another cleaner-burning fuel, air pollutants were reduced by 400-thousand tons from 1995 to 2000. It’s the equivalent of taking 16-million cars off the road. Harkin testified this morning at a Senate committee hearing on ethanol.