By David Shepardson
WASHINGTON (Reuters) - The U.S. Environmental Protection Agency told Fiat Chrysler Automobiles NV <FCAU.N> in November 2015 it suspected some of its vehicles had at least one "defeat device" which improperly bypassed emissions controls, emails disclosed under a public records request on Friday show.
The EPA and California Air Resources Board accused Fiat Chrysler in January of using undisclosed software to illegally allow excess diesel emissions in 104,000 U.S. 2014-2016 Jeep Grand Cherokees and Dodge Ram 1500 trucks. Fiat Chrysler did not immediately comment on the public records.
Byron Bunker, director of the EPA's Transportation and Air Quality compliance division, said in a January 2016 email to Fiat Chrysler obtained by Reuters under the Freedom of Information Act that he was "very concerned about the unacceptably slow pace of the efforts to understand the high NOx emissions."
NOx refers to the nitrogen oxides in polluted air.
Bunker's email said the EPA had told Fiat Chrysler officials at a November 2015 meeting that at least one auxiliary emissions control device appears to violate the agency's regulations.
Mike Dahl, head of vehicle safety and regulatory compliance for Fiat Chrysler's U.S. unit, responded in a separate email that the company was working diligently and understood EPA's concerns. He added that if EPA declared vehicles to contain defeat devices, it would result in "potentially significant regulatory and commercial consequences."
The documents redacted the vehicles named, but two officials briefed on the matter said they referred to diesel models.
(Reporting by David Shepardson; Editing by Chris Reese and Richard Chang)