Manufacturing of the Prius emits more of certain emissions than is average for a vehicle in its class.

The Toyota Prius isn't as environmentally-friendly to produce as it is to drive. And that's according to a study by Toyota itself.

In studying the Prius' lifetime environmental impact, Toyota found that production of the hybrid model came in under average compared to other vehicles in terms of emissions of non-methane hydrocarbons and particulates. This is due to the requirements of making the electric motor and the nickel-metal hydride batteries, as well as other parts such as the inverters, which create more such emissions. When measured against other cars in its class on the manufacturing side, the Prius was below average in all five of the emissions categories involved.

Of course, the Prius did fare better than average compared to other vehicles in its segment in terms of C02 emissions, nitrogen oxide (NO) and sulfur oxide over its lifetime.

Toyota said it will use the results of the study to improve environmental emissions in its manufacturing of not just the Prius but the other eight models it studied, which include the Lexus RX 450h and HS 250h.

Prius efficiency comes with environmental price