Superior Refinery rebuild

The refinery employs approximately 350 workers, and its more than US$29.9 million annual payroll contributes to economic growth throughout the Superior-Duluth area. The Superior Refinery pays more than US$2.2 million in property taxes and US$48 million in annual spending with contractors and vendors.

The Superior Refinery has been part of the Superior community since 1951 and is a strategic asset in Cenovus’s value chain.

This modernized facility has a 49,000 bbls/d throughput capacity and will produce a full slate of products for the region, including asphalt, gasoline and diesel.

In the first half of 2023, the Superior Refinery safely restarted. The refinery was rebuilt with enhanced safety equipment, incorporating advances in technology and efficiencies made across the refining industry, including:

  • A new control system throughout the refinery to improve safety and operating performance through enhanced safety shutdowns and process control.
  • New crude and fluid catalytic cracking process units which include enhanced safety measures, such as advanced technology and instrumentation to monitor performance in real-time and ensure the operations and engineering staff can carefully assess performance.
  • A new power feed and power distribution centre to stabilize power to the units and reduce the risks of refinery upsets due to power outages.
  • New training materials that combine classroom and field training, along with directed training by subject matter experts.

We’ve completed Process Hazard Analyses for both new areas and those not impacted by the incident, and the results are being incorporated into commissioning and operations activities.

Commissioning activities began in 2022 as systems became ready and the refinery introduced crude oil in mid-March 2023 and increased throughput throughout the second quarter.

Contact information

Superior Refinery

Media inquiries
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Information about hydrogen fluoride (HF)

As an introduction to how the petroleum refining industry uses hydrogen fluoride (HF), Cenovus recommends watching this short video from the American Fuel and Petrochemical Manufacturers.

The Superior Refinery produces a full slate of products, one of which is high octane gasoline which requires the use of HF as part of the alkylation process. HF is widely employed across the refining industry and has been used safely at the Superior Refinery for nearly 60 years. It is important to note our layers of safety and risk mitigation protocols worked as designed during the 2018 incident and no HF was released.

As the Superior Refinery implements advanced technologies as part of our rebuild, we continue to work with third-party experts on numerous safety programs, including enhanced safety measures for the HF alkylation unit. While the Superior Refinery’s existing safeguards operated as intended in the 2018 incident, as part of our comprehensive approach towards HF safety we are implementing additional technology and safety measures to rapidly detect and mitigate a release from the HF unit. Some of the new technologies and safety measures we are using in the refinery include:

  • More about HF

    Early detection

    • Enhanced acid-detecting paint program that changes colours if HF leaks from connection points within the unit.
    • Enhanced HF leak detection, including additional HF detectors within the unit and a new perimeter laser leak detection system surrounding the unit.
    • Dedicated video cameras to provide continuous surveillance of the alkylation process and equipment, and, if needed, to facilitate a response to a potential leak.

    Rapid response

    • Seven new remote-control water cannons which are a highly effective method of addressing HF vapours, if needed.
    • Improved water cannon spray nozzles which enable the refinery to form a dense water barrier or “water wall” around potential HF releases within the unit. 
    • Providing assistance to the Douglas County Emergency Management Department on its emergency community alert system and community evacuation plan, including interactive drills to ensure emergency responders are prepared in the event of a release.

    Isolation and containment

    • Additional emergency isolation valves to quickly limit and isolate potential leaks, if needed.
    • New HF storage tank and rapid acid transfer system, which can quickly transfer HF to an independent secure holding tank in the event of an emergency situation.

    All of these improvements will be installed prior to restart of the HF unit at the Superior Refinery and ensure our system meets or exceeds industry standards for safety at HF units.

    The Superior Refinery’s priority is the safety of our employees, contractors, and the communities we serve. Our employees at the Superior Refinery, and local public safety personnel undergo rigorous HF safety and handling training, and in every community where we operate.


Information about per-and polyfluoroalkyl substances (PFAS)

Per-and polyfluoroalkyl substances (PFAS) are a group of chemicals that have been manufactured and used in a variety of industries around the globe since the 1940s. Firefighting foam or aqueous film-forming foam (AFFF) containing PFAS has been widely used by both public and private entities for emergency response. Typical users of AFFF include federal, state and local governments for emergency response as well as the private sector engaged in activities such as PFAS manufacturing, emergency response at airports and in the petrochemical industry, and firefighting training facilities. PFAS can create a source for contamination of soil, surface water and/or groundwater. 

  • More about PFAS

    While AFFF containing PFAS was used during the 2018 incident, the Superior Refinery acted quickly to capture the majority of the impacted water used to extinguish the fire so that it could be treated for PFAS. Discharges from the refinery’s on-site wastewater treatment plant to Newton Creek since the incident have tested “non detect” for PFOS and PFOA, which are the two long-chain PFAS (commonly called C8) compounds regulated by the Wisconsin Department of Natural Resources. 

    As part of the rebuild, the Superior Refinery has upgraded its on-site wastewater treatment plant to route discharge to the City of Superior’s Publicly Owned Treatment Works rather than discharging to Newton Creek. This new system includes stormwater from areas impacted by AFFF from the incident which will continue to be treated for removal of PFAS before discharging to the city’s treatment works. 

    The above contains forward-looking statements identified by words such as “committed”, “continue”, and “will”, or similar expressions based on our current expectations, estimates, projections and assumptions related to our business. Actual results could differ materially due to adjustments to our plans and the impact of events, risks and uncertainties discussed in our annual Management Discussion & Analysis, available on our website at