Elmhurst drivers are paying close to $4.83 per gallon for regular unleaded, roughly 60 cents more than the national average, and the gap traces to a chain of refinery breakdowns less than an hour south on I-55.

The Chicago metro average for regular gas hit $4.83 on Oct. 22, according to AAA. The national average stood at $4.27. Illinois diesel averaged $6.56 per gallon, down from a record $6.83 on Sept. 23 but still nearly 80% higher than a year ago.

Gov. JB Pritzker declared the entire state a diesel disaster area on Oct. 6, Shaw Local reported. His executive order directs the Illinois Department of Revenue and Illinois State Police not to impose penalties for selling or using tax-exempt, red-dyed diesel fuel on highways through Dec. 31. President Donald Trump signed a separate federal order allowing highway use of dyed diesel.

Fuel retailers remain cautious. Nate Harris, CEO of the Illinois Fuel and Retailer Association, told Shaw Local that criminal-liability questions are unresolved and advised retailers to wait for clarification before selling dyed diesel for on-road use.

Why prices spiked

Three overlapping refinery disruptions across the Great Lakes region are behind the surge, according to RE Journals.

The ExxonMobil refinery in Joliet, a 275,000-barrel-per-day plant in Will County that produces roughly 11 million gallons of gasoline and diesel daily, suffered a total power outage on Sept. 13. The shutdown forced an emergency flaring event visible on site, according to industry publication ChemNet. That single facility accounts for about 6% of all Midwest refining capacity. Its fuel feeds pipelines serving Illinois, Indiana, Iowa, Michigan and Wisconsin.

Before the Joliet plant fully recovered, ExxonMobil shut a 50,000-barrel-per-day catalytic reformer at the same refinery on Oct. 20 after monitors observed decreased stack activity and elevated flaring, Texas Energy Report reported. An ExxonMobil spokesperson said Oct. 21 the company was working to resolve an operational issue but gave no restart timeline.

The Joliet outages coincided with planned maintenance at the Cenovus refinery in Lima, Ohio, which took another 185,000 barrels per day offline starting in September, according to RE Journals. The BP Whiting refinery in Indiana, the Midwest's largest, has also been running with restricted capacity. About 800 BP workers have been locked out since March 19 in a contract dispute with the United Steelworkers, In These Times reported.

Local costs climbing

The Bureau of Labor Statistics reported that gasoline prices in the Chicago-Naperville-Elgin area, which includes DuPage County, rose 6.3% from August to September. Year over year, the gasoline index climbed 28.9%.

In DuPage County, the cheapest reported price for E15 gas was $3.99 per gallon during the week ending Sept. 19, according to the DuPage Policy Journal citing GasBuddy data. The county averaged $4.52 per gallon for E15 that week. Prices have risen since then.

Neighboring Villa Park budgeted $290,000 for gas and diesel for its municipal fleet of more than 100 vehicles in 2024, according to village public works budget documents. How much the current spike has added to that line item is unclear. No updated 2026 figures for Villa Park's or Elmhurst's municipal fuel costs were available.

What comes next

Patrick De Haan, head of petroleum analysis at GasBuddy, told the Chicago Tribune that diesel prices may decline slightly in the weeks ahead as the Joliet plant resumes operations. Per-gallon diesel had already dropped more than 25 cents since the Sept. 23 peak.

Longer-term relief is uncertain. "A lot of that is a function of the continued evolution in the situation between the U.S. and Ukraine, and the U.S. and Iran," De Haan told the Tribune. "If we see some improvement in tensions there, then we could see some relief."

RE Journals noted that much of the current pressure stems from a temporary regional bottleneck and that prices should stabilize as the Joliet refinery returns and BP Whiting's maintenance ends. The Oct. 20 catalytic reformer shutdown complicates that forecast. ExxonMobil has not disclosed a restart date for the unit.