A number of Colorado gas stations distributed contaminated fuel to customers this week, state officials said.
Diesel fuel was mixed with regular unleaded gasoline and that contaminated mixture was distributed to gas stations run by Costco, Murphy Express and King Soopers across the Denver metro, according to Colorado's Division of Oil and Public Safety.
Customers at the affected gas stations who sought regular unleaded gasoline instead received the diesel-contaminated mixture.
State officials believe the contaminated fuel originated from the HF Sinclair terminal in Henderson, and was then sent out to "numerous" gas stations. The fuel was distributed to the gas stations between 2 p.m. Wednesday and 6 a.m. Thursday, according to the division, which began receiving complaints about bad gas on Thursday.
A state investigator on Thursday confirmed that gas at the Costco on River Point Parkway in Sheridan was contaminated.
"Station owners are working quickly to stop sales of the contaminated gasoline and have it replaced with the right fuel," read a Friday statement from the Division of Oil and Public Safety.
At least 13 King Soopers gas stations were affected, King Soopers spokeswoman Jessica Trowbridge said in a statement. Representatives for Costco, Sinclair and Murphy Express did not return requests for more information Friday.
"As soon as we became aware of the issue, we took immediate action by shutting down the impacted fuel lines and dispatching teams to perform thorough diagnostics," Trowbridge said.
A vehicle filled with contaminated fuel will quickly stall out, said Steve Martindale, service director at Phil Long Ford Denver. Two vehicles had already come into the dealership by Friday with the issue, he said. One driver made it barely out of the gas station's parking lot before the car stalled.
"When you get diesel in gas, diesel takes a lot more heat to ignite than gasoline does, and a gas engine can’t ignite the diesel, it doesn’t get hot enough," he said. "So what is happening is the engine will stall, because it is acting like it is not getting fuel."
A vehicle with a gas tank filled with contaminated fuel might drive for 200 feet before stalling, he said, while a vehicle that was just topped off with contaminated fuel would drive farther.
Impacted drivers can expect to spend around $1,000 to fix the problem, in addition to a tow bill, Martindale said. Putting diesel into a gas engine is far less damaging than putting gas into a diesel engine, he noted.
"Itap definitely not a good situation and I wouldn't wish that on anybody, but it is not going to cause catastrophic failure," he said.
Colorado gas stations impacted by contaminated fuel
- 14967 Candelas Pkwy., Arvada
- 25701 E. Smoky Hill Road, Aurora
- 17000 E. Iliff Ave., Aurora
- 3050 S. Peoria St., Aurora
- 1045 S. 1st St., Bennett
- 12167 Sheridan Blvd., Broomfield
- 2355 W. 136th Ave., Broomfield
- 7284 Lagae Road, Castle Pines
- 750 N. Ridge Road, Castle Rock
- 5125 W. Florida Ave., Denver
- 1611 Pace St., Longmont
- 12959 S. Parker Road, Parker
- 17761 Cottonwood Drive, Parker
How to file a claim if your vehicle was damaged by contaminated gas
Drivers impacted by contaminated gas can reach out to the gas station where they purchased the fuel, and can file a complaint with the Division of Oil and Public Safety.
To file a complaint, call 303-866-4967 or and email it to cdle_oil_inspection@state.co.us.
King Soopers customers who believe they received the contaminated fuel should contact their local store for assistance, Trowbridge said.
Updated 3:06 p.m. Friday, Jan. 9, 2026: This article was updated to correct the phone number people can call to file a complaint about contaminated gas.
