Nathan Bomey

USA TODAY

DETROIT — U.S. regulators accused Fiat Chrysler Automobiles of violating emissions standards in more than 100,000 diesel vehicles, spawning concerns that the company could become ensnared in a scandal like the one that engulfed Volkswagen Group.

The Environmental Protection Agency said Thursday that Fiat Chrysler illegally installed software on about 104,000 pickups and sport-utility vehicles that spewed harmful pollutants while failing to disclose the technology.

The allegations involve the 2014, 2015 and 2016 Jeep Grand Cherokee and light-duty Ram 1500 pickup trucks with 3-liter diesel engines.

The EPA said the automaker installed eight different undisclosed software programs on the vehicles, collectively causing them to spew harmful nitrous oxide emissions, which can exacerbate respiratory conditions.

"This is a clear and serious violation of the Clean Air Act," said Cynthia Giles, assistant administrator for the EPA’s Office of Enforcement and Compliance Assurance. "There is no doubt they are contributing to illegal pollution."

Fiat Chrysler CEO Sergio Marchionne blasted the EPA in a quickly arranged media call, saying he was offended by the agency's "incredibly belligerent" attacks on the auto industry. He said his company had done nothing illegally, and to try to dispel comparisons to Volkswagen's crisis.

"There is nothing in common between the VW reality and what we are describing here," he said. It's "absolute nonsense" to suggest so, he said, and anyone who disagreed with him is "smoking illegal material." Marchionne insisted that Fiat Chrysler has been forthright.

"We're trying to do an honest job here. We're not trying to break the bloody law," he told reporters.

Marchionne rejected the suggestion that rogue employees could have schemed to violate EPA laws. "If I found a guy like that, I would have hung them on a door," he said.

VW pleads guilty to conspiracy, obstruction of justice; 6 execs charged

Fiat Chrysler (FCAU) shares trading on the New York Stock Exchange were down about 9% after initially tumbling 14% on the news as investors fretted about the financial implications.

New York Attorney General Eric Schneiderman said his office would investigate Fiat Chrysler. Marcionne said he believes the U.S. Justice Department is assisting the EPA with its investigation.

Several analysts said the company's sin may have been solely of disclosure, not an intentionally deceptive act like that at VW.

"Software which adjusts the emissions of an engine is standard practice across the industry," Evercore ISI analyst Arndt Ellinghorst said in a note to investors. "It is the failure to disclose which seems to be the primary cause of concern at the EPA."

The EPA has the authority to fine automakers up to $44,539 per vehicle for the worst violations of the Clean Air Act. The agency threatened possible fines Thursday if it determines that the software installed on the vehicles qualifies as illegal "defeat devices" under U.S. laws.

Kelley Blue Book analyst Rebecca Lindland said there was no indication that Fiat Chrysler intentionally cheated.

"They're not meeting the standards, but right now, it doesn't appear to be the same type of deliberate act that Volkswagen admitted to," she said.

Lindland said the mistake might have been a failure to mention the technology when requesting EPA certification to sell the vehicles.

"It's like bringing a calculator to your math test — you're allowed to bring it, and it's one thing to have it on your desk, but it's another thing to have it in your lap," she said.

Fiat Chrysler said in a statement that it offered to the EPA to develop software fixes to "further improve emissions performance" because it wants to "resolve this matter fairly and equitably."

The vehicles were programmed with software that violated standards and was not disclosed to the EPA, Giles said. In lab testing, the vehicles met standards, but at high speeds and in extended driving, they violate regulations, the EPA's Giles said.

"That means that the vehicles were sold illegally," she said.

The EPA said it discovered the alleged violations after expanding its testing of on-road vehicle performance following the Volkswagen scandal.

Volkswagen admitted to cheating emissions laws on more than half a million vehicles and has agreed to criminal and civil settlements totaling nearly $22 billion. Six VW executives were charged Wednesday with allegedly weaving a conspiracy to dodge regulations while the company pleaded guilty to similar charges on a corporate level.

In Volkswagen's case, vehicles spewed NOx emissions at rates up to 40 times the U.S. standard. Giles declined to provide a comparable assessment for Fiat Chrysler.

Marchionne sought to distance Fiat Chrysler from VW.

"To be perfectly honest, I think it's being blown out of proportion," he said. "I find this to be a bizarre characterization of FCA's activities, and we will defend our behavior."

Unlike VW, the EPA has not ordered Fiat Chrysler to halt sales of diesel vehicles accused of violations. Marchionne said he would not stop sales proactively.

It's not unusual for Marchionne to take a combative stance against a federal regulatory agency. Marchionne pushed back against the National Highway Traffic Safety Administration in 2013 when the agency initially recommended a recall of 2.7 million Jeep SUVs for potentially dangerous rear-mounted fuel tanks.

Eventually, the agency agreed to allow FCA to reduce the recall to include 1.56 million Jeep Grand Cherokees for model years 1993 to 2004 and the Jeep Liberty model years 2002 to 2007.

The following year, the NHTSA was again critical of the automaker for the slow repair rate of those Jeeps.

Contributing:Brent Snavely, Detroit Free Press

Follow USA TODAY reporter Nathan Bomey on Twitter @NathanBomey.