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 50,000 bbls/d throughput capacity and will produce a full slate of products for the region, including asphalt, gasoline and diesel. We’re rebuilding the facility with state-of-the-art equipment, incorporating many technology and efficiency advances from across the refining industry.

We value safety above all else. The Superior Refinery has the highest safety standards and uses best practices. Cenovus’s investment in the Superior Refinery rebuild, includes many new safety enhancements.

Notable equipment upgrades include:

  • A new control system throughout the refinery to improve safety and operating performance through enhanced safety shutdowns and process control.
  • New state-of-the art slide valves in the fluid catalytic cracking unit with advanced 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 ensure stable power to the units and reduce the risks of refinery upsets due to power outages.

New training materials combine classroom and field training, delivered by subject matter experts, and include the use of simulators which mirror control room equipment and cover a full range of operating conditions.

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 are continuing in 2023. We expect to ramp up in the first and second quarters of 2023.

Superior Refinery newsletter
  • Read the latest community newsletter - Spring, 2022 (PDF)
  • Read the previous community newsletter - May, 2021 (PDF)
  • Learn more from our fact sheet (PDF)
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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 Cenovus 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, Cenovus continues to work with third-party experts on numerous safety programs, including enhanced safety measures for the HF alkylation unit. While Cenovus’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.

    Cenovus’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, Cenovus remains committed to world-class safety performance and environmental, social and corporate governance leadership.


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. 

    Cenovus has formed an internal steering committee in response to the growing human health and environmental concerns related to PFAS. This group has assisted the Superior Refinery and other Cenovus facilities in the U.S. and Canada in taking proactive steps to minimize the risk posed by PFAS, such as transitioning away from formulations of AFFF that contain PFOS and PFOA.

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