Regular gas in DuPage County averaged $4.30 per gallon for the week ending Sept. 5, according to the DuPage Policy Journal. Six weeks later, the Chicago metro average had climbed to $4.83, according to AAA data from Oct. 22. The national average sat at $4.27.

The gap traces to a cluster of refinery breakdowns in the region. 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 that forced an emergency shutdown, according to industry publication ChemNet. Flames and black smoke from the plant's flare system were visible on site.

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 could fully recover, ExxonMobil shut a 50,000-barrel-per-day catalytic reformer at the same site on Oct. 20, Texas Energy Report reported. An ExxonMobil spokesperson said Oct. 21 the company was working to resolve an operational issue but gave no restart timeline.

Two other disruptions compounded the squeeze. The Cenovus refinery in Lima, Ohio, took 185,000 barrels per day offline for planned maintenance starting in September, according to RE Journals. The BP Whiting refinery in Indiana, the Midwest's largest, has been running with restricted capacity since about 800 workers were locked out March 19 in a contract dispute with the United Steelworkers, In These Times reported.

DuPage County commuters feel the pinch

At College of DuPage in Glen Ellyn, students say the price spike is reshaping their budgets. Jorge Muñoz, an electrical engineering student who commutes from West Chicago, told the COD Courier that fill-ups that once cost $30 to $40 now run about $80.

Demand for the college's transportation assistance program has increased, the Courier reported. Melissa Jankauski, program manager for Special Student Resources, said COD doubled the value of its gas cards from $25 to $50 after staff determined the original amount was not enough.

"We soon realized that $25 isn't enough to sustain a full tank of gas," Jankauski told the Courier.

School bus budgets under pressure

Diesel in Illinois averaged $6.56 per gallon on Oct. 22, according to AAA, down from a record $6.83 on Sept. 23 but still nearly double the price a year ago. Gov. JB Pritzker declared the entire state a diesel disaster area on Oct. 6, directing the Illinois Department of Revenue and Illinois State Police not to penalize the sale or use of tax-exempt red-dyed diesel through Dec. 31, Shaw Local reported.

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%.

Glenbard Township High School District 87's board approved an amendment to its emergency transportation contract with Durham at its Sept. 14 meeting, according to board minutes. The amendment covers the 2026-27 school year including summer school. The minutes do not detail fuel-cost impacts on the district's budget.

Across the suburbs, districts that run their own bus fleets have been hit hardest. Naperville Unit District 203, which operates more than 120 diesel buses for about 16,000 students, expects to spend an extra $300,000 on fuel this school year if diesel prices hold, the Chicago Tribune reported.

What comes next

Patrick De Haan, head of petroleum analysis at GasBuddy, told the 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.

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.