In a July 5 letter to the EPA, Rep. Jim Sensenbrenner (R-WI), vice chairman of the House Committee on Science, Space, and Technology, noted that automobile manufacturers fear ethanol blends in gasoline greater than 10 percent will damage the engines of newer vehicles, reduce fuel efficiency, and void warranties. Sensenbrenner argued that the decision to approve E15 for model year 2001 and newer vehicles should be voided owing to the fact that the agency was overly reliant on “narrow” testing by DoE that did not consider the effects on vehicle engines. The letter sought to find out whether EPA initially considered the effects of E15 on engines before granting two partial waivers allowing its use and whether vehicle performance will be impaired with the use of E15.