​​​​​​​Imperial seeks renewal allowing some refinery changes without new approval amendments

Imperial Oil has asked Ontario to renew an environmental approval that allows certain changes at its Sarnia refinery without requiring a new approval amendment each time. The company would still have to remain within prescribed operating and emissions limits, while the public has until Nov. 12 to comment.

Imperial Oil is asking Ontario to renew an environmental approval that gives its Sarnia refinery flexibility to make certain operational changes without seeking a new provincial approval amendment each time.

The application was posted to Ontario's Environmental Registry on Sept. 28 and concerns Imperial's refinery at 602 Christina St. S.

Rather than seeking approval for a particular new project, Imperial is applying to renew the “Limited Operational Flexibility” attached to its existing air and noise Environmental Compliance Approval.

Under Ontario's approval system, operational flexibility allows a facility to make certain predefined changes to equipment or processes without returning to the province for an amendment each time, provided those changes remain within an operating envelope established by the approval.

Examples identified in provincial guidance include adding pollution-control equipment, changing the rate or composition of raw materials and debottlenecking processes.

The flexibility does not give a company unrestricted authority to change a facility.

For air approvals, the operating envelope includes a facility production limit, along with environmental performance requirements. Changes outside that envelope require another application to amend the Environmental Compliance Approval.

Imperial's Sept. 28 notice does not identify a particular refinery expansion or new piece of equipment being proposed as part of the renewal.

It says emission sources associated with refinery operations include laboratory fume hoods, material handling, storage tanks, catalytic cracking, flares and cooling towers.

Among the contaminants listed in the renewal notice are acrolein, cobalt, naphthalene, vanadium, toluene and particulate matter.

Their inclusion does not mean Imperial is proposing to begin emitting those contaminants for the first time, nor does the notice say their emissions will increase. They are emissions associated with operations covered by the approval being renewed.

Imperial's Environmental Compliance Approval, numbered 6254-9LVQ3V, was originally issued in October 2015 and has since been amended as equipment and operations at the Sarnia facility have changed.

Some recent changes have gone through separate applications to amend that approval.

In August, Ontario approved an amendment allowing Imperial to add a wet gas scrubber and an amine-based flare gas treatment system and increase sulphur-recovery capacity.

That approval lists refinery emissions including sulphur dioxide, benzene, benzo(a)pyrene, nitrogen oxides and several metals.

Another amendment approved in January added three permanent vapour combustors and a permanent thermal oxidizer. It also approved a temporary thermal oxidizer that can be brought to the site when needed to control volatile organic compound emissions.

Other amendments in recent years have allowed temporary thermal oxidizers to control benzene and other volatile organic compound emissions during work involving storage tanks and benzene rail loading.

Those modifications were approved through separate amendments to Imperial’s Environmental Compliance Approval.

Ontario requires applicants seeking operational flexibility for air emissions to establish an overall facility production limit or capacity. That limit becomes one of the boundaries on what can be changed without another amendment.

The Sept. 28 Imperial notice says the renewed approval will contain a production limit, but does not provide the numerical limit in the online posting.

The Environmental Registry notes that some supporting material may not be available online and can be requested for in-person review through the Ministry of the Environment, Conservation and Parks.

For context, Imperial reported that its Sarnia refinery processed an average of approximately 113,000 barrels of crude oil per day in 2025. The company's rated refinery capacity at the end of the year was 124,000 barrels per day.

Those figures describe actual refinery throughput and rated capacity and should not be confused with the production limit that will form part of the environmental approval.

Facilities operating under this type of approval must continue demonstrating compliance with applicable air requirements and conditions imposed by the ministry. Modifications outside the approved operating envelope require another amendment.

Ontario is accepting public comments on Imperial's renewal application for 45 days.

The consultation closes at 11:59 p.m. on Nov. 12. After the consultation and ministry review, the province will determine whether to renew the operational-flexibility conditions and what conditions will apply.