Canadian Refinery Shutdown Could Spike Northeast Diesel Prices This Fall

How long will the Irving Oil shutdown last?

Irving Oil's Saint John refinery in New Brunswick will shut down from early September to mid-November for a maintenance turnaround, the company announced on its website. The plant processes 300,000 barrels of crude a day and supplies gasoline, diesel, and heating oil to Maine, Massachusetts, and other northeastern states. Irving has not disclosed which units are being worked on or whether it has arranged alternate supply for customers during the outage.

The timing hits when U.S. refiners are already running hard to meet demand strained by the U.S.-Israeli war on Iran and lingering effects of Russia's war on Ukraine. Pump prices nationwide averaged above $5 a gallon as of mid-July. Diesel markets face particular pressure, and the Saint John shutdown removes a major import source just as heating oil stocks typically fall and prices spike in colder months.

Why this shutdown matters for small fleets

The Saint John plant is Canada's largest oil refinery. Northeastern states that import fuel from the facility will see tighter supply at a time when U.S. refiners are deferring maintenance to profit from record margins for turning crude into fuels. That strategy risks unplanned outages, which would compound the supply squeeze.

Irving regularly conducts fall maintenance. The plant underwent a 30-day turnaround in 2025, including upgrades to a gasoline-making unit, and a five-week turnaround in 2024 during the same period. This year's shutdown runs longer than either of the prior two, overlapping with the start of heating oil season.

Diesel and heating oil exposure

Heating oil stocks fall and prices spike in colder months as consumption rises. The Saint John refinery supplies heating oil to northeastern states for home heating in winter. A two-month outage starting in early September means the plant will be offline during the seasonal build period when distributors stock up ahead of peak demand.

Diesel markets are already strained. Conflicts in the Middle East and Eastern Europe have placed particular pressure on refiners that make diesel. U.S. refiners are running at capacity to supply a tight market, but the Irving shutdown removes 300,000 barrels a day of processing capacity from a region that relies on imports to meet demand.

What fleets in the Northeast should watch

Fleets running lanes in Maine, Massachusetts, and surrounding states should expect tighter diesel availability and higher rack prices starting in September. The shutdown removes a major regional supply source at a time when U.S. refiners are already stretched. If any domestic refiners experience unplanned outages while deferring maintenance to maximize output, the supply cushion disappears.

Heating oil prices will also climb as the outage overlaps with seasonal stocking. Fleets that heat facilities or run reefer units on heating oil should lock in contracts before September if possible. Spot prices typically spike in fall as distributors compete for limited supply.

Irving did not respond to questions about alternate supply arrangements for customers. That leaves importers and distributors scrambling to source fuel from other refineries or increase imports from Europe, both of which add cost. Those costs show up at the pump and on fuel cards.

The bill for a 10-truck fleet

A 10-truck fleet running 1,000 miles per week per truck at 6 miles per gallon burns roughly 1,667 gallons a week, or about 21,667 gallons over a 13-week period matching the Irving shutdown. If diesel prices in the Northeast climb 30 cents a gallon during the outage (a conservative estimate given current market strain and heating oil demand), that fleet pays an extra $6,500 over the fall. Larger fleets or those running higher weekly miles face proportionally higher bills.

Fleets with fuel hedges or contracts locked in before September will avoid some of the spike. Those buying spot fuel or on floating-price contracts will see the full hit. The Irving shutdown is routine maintenance, but the timing and duration land in a market with no slack.