A mix-up of regular and diesel fuel at several gas stations throughout Colorado could result in millions of dollars in damages, an industry expert said Friday.

Tim Jackson, former president and CEO of the Colorado Automobile Dealers Association, said that those who accidentally — through no fault of their own — filled up their vehicle with contaminated fuel could see it seriously damage the engine or even make the car not able to start entirely.

“A gasoline engine just isn’t designed to handle diesel fuel, that’s why if’s going to either knock or completely shut off if it’s got too much of this fuel in it,” Jackson said. “Damage to the engine, where it would have to get overhauled or replaced, that’s where it will get really expensive.”

Officials from Colorado’s Division of Oil and Public Safety announced Friday morning that they are investigating complaints that multiple gas stations across the state received diesel in regular gas shipments, according to The Denver Gazette’s news partners 9News.

Customers had filed more than 200 complaints with about six gas stations across Colorado as of 11:30 a.m. Friday, the division’s Petroleum Program Manager Zach Hope told 9News. Anyone who filled up after 2 p.m. Wednesday or any time on Thursday may have been affected by the mix-up.

The agency is investigating gas primarily at three retail outlets: King Soopers, Costco and Murphy Express, Hope said. It appears the gas came from a Sinclair terminal in Colorado.

“I’m assuming it happened with more than one truck, maybe several trucks, because these tankers that you see on the road or pulling into a gas station, they will usually empty out at a single station,” Jackson said. “I don’t know what could have caused it, but whatever caused it to get these gasoline tankers fueled with diesel, that’s on somebody.”

For those who filled up with the contaminated fuel, Jackson said they should stop driving immediately and bring their vehicle into a dealership or repair shop to get it looked at.

“Towing a car isn’t cheap, but it’s less expensive than having to replace an engine,” Jackson said.

Anyone who may have been affected by the contaminated fuel can can file a complaint with the Division of Oil and Public Safety.

For more on this story and others, please visit The Denver Gazette’s news partner 9News.