Toyota’s Prius hybrid has come under fire recently for not being as eco-friendly as its maker would have you believe but now, one of its key developers, Toyota’s US manager of its Advanced Technologies Group Bill Reinert, has come out defending the car. Last year, a study conducted by CNW Marketing-Research revealed that the energy cost per mile for the Prius was $3.25 over 100,000 miles. To put that into perspective, the behemoth Hummer H2’s energy cost was only $1.95 per mile over 300,000 miles.

According to Reinert, the methodology behind the findings was questionable and that the research firm hasn’t released any of its data to be independently scrutinized. The Toyota staffer also claims the findings have been refuted “by every top science group of the world,” reports GoAuto.

The Toyota Prius is not the only hybrid to be criticized for not being as green as its maker claims. Honda is being sued because an owner of its Civic Hybrid claims his car doesn’t come anywhere near meeting the advertised mileage claim of 49mpg in the city and 51mpg on the highway. Honda’s ad claimed the car could travel up to 650 miles on a single tank, which would mean drivers have to average 51mpg. The California man suing the carmaker, John True, claims he averaged just 32mpg after driving 6,000 miles.