The U.S. Environmental Protection Agency is not satisfied with research done so far on the environmental impacts of a potential new highway in the Phoenix area.

A statement issued by the EPA said the report lacked enough information regarding air quality, human health, or any other type of damage the freeway could cause.

The Arizona Department of Transportation had an issue with that finding. Timothy Tait, the ADOT's assistant communication director, defended the study and said the state remains on track to finalize it next summer, The Associated Press reported earlier Monday.

"Many of EPA's comments were either contrary to state law or against guidance that the Federal Highway Administration provides," Tait said. "In some instances, it showed a little bit that the EPA was...out of touch with the project, and the realities of transportation in metro Phoenix. And, in other cases they simply renewed the disagreements between two federal agencies."

The ADOT spent $21 million studying environmental effects of the proposed route for South Mountain Freeway, which would connect the Interstate 10 on the southeast and western sides of Phoenix.

AP reported that a different federal agency, the Federal Highway Administration, will decide whether the proposed highway will receive federal funding.

Arizona doesn't have to follow the EPA's findings, because final approval of the project comes from the highway administration. The EPA's role is strictly advisory.

If built, South Mountain Freeway would give travelers on I-10 a way to bypass downtown Phoenix.