King Soopers & HF Sinclair Face Class Action Over Diesel-Contaminated Gasoline Sold Across Colorado

Multiple class action lawsuits have been filed in Colorado courts against HF Sinclair Corporation and Dillon Companies LLC (doing business as King Soopers Fuel Centers), along with Costco and Murphy Express, after diesel-contaminated gasoline was distributed to 49 Front Range gas stations on January 7–8, 2026.

 The contamination resulted from workers at the HF Sinclair terminal in Henderson mistakenly leaving a valve open, which allowed diesel fuel to mix with regular unleaded gasoline — ultimately affecting more than 1.6 million gallons, of which 365,694 gallons were sold to consumers. No settlement has been announced. The lawsuits are currently in the litigation phase, and class certification has not yet been granted.

Quick Facts

• Lawsuit Type: Proposed class action (multiple filings); no class certified yet
• Defendants: HF Sinclair Corporation / Sinclair Oil; Dillon Companies LLC (King Soopers Fuel Centers); Costco Wholesale Corporation; Murphy Oil USA (Murphy Express)
• Current Status: Active litigation — class certification pending in Denver District Court and Adams County Court
• Who May Be Affected: Colorado consumers who purchased unleaded regular- or plus-grade gasoline from any of the 49 affected Front Range stations between approximately 2 p.m. January 7 and 6 a.m. January 8, 2026
• Settlement Amount: None announced — TBD
• Claim Deadline: Not yet established — TBD
• Lead Plaintiff Attorneys: Franklin D. Azar & Associates, P.C. (303-800-0000); Berger Montague
• Regulatory Authority: Colorado Division of Oil and Public Safety (CDOPS)

Current Status & What Happens Next

The lawsuits are in the early litigation phase. Key developments to watch:

• Class certification has been requested by plaintiff attorneys but had not been granted as of mid-January 2026. Courts must formally certify a class before any group settlement or collective recovery can proceed.
• Colorado’s Division of Oil and Public Safety completed its investigation and released findings on March 6, 2026, confirming the cause of contamination was a valve left open by Sinclair employees.
• King Soopers retained Sedgwick, a third-party claims administrator, to handle individual consumer reimbursements — but some consumers reported being offered limited settlements in exchange for signing releases waiving future legal claims. Affected consumers should consult a qualified attorney before signing any such release.
• No trial date has been set. Given the volume of plaintiffs and number of defendants, this litigation may take years to resolve.

What the Lawsuit Alleges

According to the 21-page complaint, HF Sinclair Corporation and Dillon Companies LLC (King Soopers) delivered hundreds of thousands of gallons of unleaded regular- and plus-grade gasoline to dozens of Colorado gas stations on January 7, 2026. Due to oversight in quality control and inspection, the fuel delivered to retailers had been mixed with diesel fuel.

The lawsuit claims the defendants are guilty of negligence, violating the Colorado Consumer Protection Act, defective product liability, and breaching the warranty of merchantability — which asserts that goods must be reasonably fit for their ordinary and intended purpose and free of defects.

The filing stresses that vehicles designed to run on unleaded gasoline can suffer catastrophic damage if that fuel is mixed with diesel. “Gas-powered vehicles are not designed to operate using diesel fuel or fuel contaminated with diesel,” the complaint states.

Additionally, the lawsuit alleges the defendants engaged in unfair and deceptive trade practices by knowingly or recklessly representing that the contaminated fuel was safe to use, and that they failed to use reasonable care to prevent the gasoline from being contaminated and subsequently sold to the public.

Who Could Be Included

The class action seeks to represent all consumers who purchased unleaded regular- or plus-grade gasoline that originated from HF Sinclair Corporation’s Henderson Terminal and was contaminated with diesel fuel.

You may be included in the class if you:

• Filled up your vehicle at one of the 49 affected Front Range gas stations — including King Soopers, Costco, Murphy Express, Safeway, Circle K, or Sinclair-branded stations
• Purchased fuel between approximately 2 p.m. on January 7, 2026 and 6 a.m. on January 8, 2026
• Experienced vehicle damage, engine issues, repair costs, towing expenses, or rental car costs as a result
• Are a Colorado resident or were in Colorado at the time of purchase

Up to 400,000 gallons of fuel may have been affected, and the Colorado Division of Oil and Public Safety received more than 600 complaints from consumers.

Settlement Details

No settlement has been announced at this time. The lawsuits remain in active litigation. This section will be updated when a settlement is proposed or approved.

However, consumers should note: King Soopers has been offering individual reimbursements through Sedgwick, a third-party claims administrator. At least one consumer reported being offered $550 to cover an insurance deductible and a tank of gas — but only in exchange for signing a release waiving all future claims related to the incident. Vehicle repair costs for some affected drivers have been estimated well above that amount.

Before accepting any individual settlement offer, consumers who suffered vehicle damage should speak with a contaminated product class action like celtic-sea-salt attorney to understand whether accepting the offer could affect their right to participate in any future class action recovery.

Prior Cases & Context

This is not the first time diesel contamination of unleaded gasoline has led to widespread consumer harm and litigation in the United States. Similar incidents at fuel terminals have resulted in class actions and substantial settlements in other states, typically covering vehicle repair costs, towing, rental cars, and consequential damages.

Sinclair did not notify the Colorado Division of Oil and Public Safety when it first became aware of the contamination on the morning of January 8 — a fact that regulators and plaintiffs may use to support claims of negligence and inadequate consumer protection. State investigators classified the event as “unprecedented” in its scale.

For a recent example of how a class action settlement of walgreens can result in meaningful consumer compensation, see how the Walgreens $100 million settlement was structured and paid out.

FAQs

Is this a class action lawsuit?

Multiple proposed class actions have been filed in Denver District Court and Adams County. Class certification has been requested by plaintiff attorneys at Franklin D. Azar & Associates, but had not been granted as of mid-January 2026. Until the court certifies a class, the lawsuits remain proposed class actions.

Has a settlement been approved?

No. There is no approved or proposed class settlement at this time. King Soopers has been offering individual reimbursements through claims administrator Sedgwick, but these are separate from any class action resolution and may require signing away future legal rights.

Who may be eligible to join the class?

Anyone who purchased contaminated fuel from one of the 49 affected Colorado Front Range gas stations between approximately 2 p.m. on January 7 and 6 a.m. on January 8, 2026, and suffered vehicle damage or related expenses as a result, may be eligible.

Is there a claim form I can file right now?

There is no formal class action claim form yet. Consumers who experienced engine issues after filling up are encouraged to contact the law firm Franklin D. Azar & Associates at 1-303-800-0000. You may also contact Berger Montague, co-counsel in a separate filing.

Where can I find official information?

The Colorado Division of Oil and Public Safety (CDOPS) has published its investigation findings and a list of affected stations. Visit CDOPS online or contact the division directly for official documentation.

What are the specific risks or damages involved?

Vehicles that run on unleaded gasoline can be severely damaged by diesel-contaminated fuel, with reported symptoms including stalling, sputtering, inability to restart, and white smoke from the tailpipe. One plaintiff reported vehicle repair costs estimated at $5,300, plus $250 for towing — far exceeding reimbursement offers made by King Soopers through Sedgwick.

Should I accept King Soopers’ reimbursement offer through Sedgwick?

Not without consulting an attorney first. At least one consumer reported that King Soopers’ claims administrator required her to sign a release waiving all future claims in exchange for a $550 payment — even though vehicle repairs in some cases exceeded thousands of dollars. Accepting this offer could prevent you from participating in any future class action settlement.

What caused the contamination?

State investigators confirmed that workers at the HF Sinclair terminal in Henderson failed to close a valve, which allowed diesel fuel to mix with regular unleaded gasoline — contaminating more than 1.6 million gallons, of which nearly 366,000 gallons were sold to consumers at 49 gas stations across the Front Range.

Last Updated: March 9, 2026

Disclaimer: This article is for informational purposes only and does not constitute legal advice. Legal claims and outcomes depend on specific facts and applicable law. For advice regarding a particular situation, consult a qualified attorney.

About the Author

Sarah Klein, JD, is a licensed attorney and legal content strategist with over 12 years of experience across civil, criminal, family, and regulatory law. At All About Lawyer, she covers a wide range of legal topics — from high-profile lawsuits and courtroom stories to state traffic laws and everyday legal questions — all with a focus on accuracy, clarity, and public understanding.
Her writing blends real legal insight with plain-English explanations, helping readers stay informed and legally aware.
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