On January 1, 2021, Cenovus Energy acquired Husky Energy to form the third largest Canadian oil and natural gas producer and the second largest Canadian refiner. Learn more at Cenovus.com.

Superior Refinery has been part of the Superior community since 1951 and is a strategic asset in the company's Value Chain. The Refinery employs almost 200 workers and its more than $27 million annual payroll contributes to economic growth throughout the Superior-Duluth region. The Refinery contributes more than $1.6 million in property tax and $48 million in annual spending with contractors and vendors.

Timeline of Superior Refinery fire and explosion:

  • In October 2018, Husky Energy purchased the Superior Refinery from Calumet Specialty Products Partners, L.P.
  • In April 2018, an explosion and fire occurred at the refinery while preparations were underway for major maintenance work. The Refinery has been shut down since the incident.
  • On January 1, 2021, Husky Energy, combined with Cenovus Energy. The Superior Refinery and its sister refinery in Lima, OH, along with several joint venture refineries in the U.S. are key assets in Cenovus's downstream business.
  • In January 2021, Cenovus reaffirmed its commitment to rebuilding the Refinery.

The rebuild project will result in a modernized facility with the same 50,000 bbls/day throughput capacity and ability to produce a full slate of products to service the region, including asphalt, gasoline and diesel. The facility is being rebuilt with state-of-the-art equipment, incorporating many advances in technology and efficiencies made across the refining industry.

Consistent with OSHA's recommendations and as part of our own due diligence, a variety of assurance activities are being conducted across the entire refinery to verify the condition and operability of the equipment and control systems. There have also been upgrades to equipment, procedures, and training. 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 crude and fluid catalytic cracking process units, including new state-of-the art slide valves with advanced instrumentation to monitor performance real-time and ensure the operations and engineering staff can carefully assess performance.
  • A new power feed and power distribution center to ensure stable power to the units and reduce the risks of refinery upsets due to power outages.

New training have been developed materials which combine classroom and field training, delivered by subject matter experts, and includes the use of simulators which match control room equipment and cover a range of operating conditions.

Process Hazard Analyses (PHAs) have been completed for both new and non-affected areas of the refinery, and will be incorporated into pre-commissioning, commissioning and operations activities.

Pre-commissioning and commissioning activities will take place throughout 2022 as components are ready, with full restart projected for the first quarter of 2023.

Hydrogen Fluoride (HF)

Hydrogen Fluoride (HF) is used as part of the alkylation process to produce high octane gasoline, an integral part of the Superior Refinery's slate of products. HF has been safely used at the Cenovus Superior Refinery for almost 60 years and is widely used across the refining industry. It is important to note that no HF was released during the 2018 incident at the Refinery and all HF safeguards worked as designed.

More about HF

Possible alternatives to HF were investigated as part of the rebuild process and a robust analysis of alkylation technologies was conducted. After a thorough technology review, engineering analyses, risk assessments and discussions with subject matter experts, the Refinery concluded that alternative technologies involved significant technology risks and/or were not yet proven on a broad commercial basis. For example, one alternative process - converting an HF Alkylation Unit to sulfuric acid has never been done in the refining industry and would present substantial technological and operational risks.

After a thorough and ongoing evaluation of HF alternatives, the decision remains to continue using HF at the Superior Refinery with significant safety equipment and processes in place. The use of alternative technologies is being monitored and evaluated as they continue to be developed and tested on a commercial basis.

We recognize the community's concerns about the use of HF. Refinery workers, many of whom live in the community, fully understand the need to maintain the highest safety standards. The Cenovus Superior Refinery is committed to world-class safety performance and environmental, social and corporate governance (ESG) leadership.

As part of the rebuild efforts, the Superior Refinery has implemented additional safety measures for the HF Alkylation Unit. These measures are being completed as part of our Consent Decree and with regulatory oversight. Some of the key upgrades include:

  • Installation of seven new remote-control water cannons which are a highly effective method of addressing hydrofluoric acid vapors, if needed.
  • Installation of a new Rapid Acid Transfer System, which can quickly transfer HF to an independent secure holding tank within the unit in the event of an incident.
  • Installation of a new HF storage tank.
  • Enhanced HF leak detection, including additional HF detectors within the unit and a new laser detection system surrounding the unit.
  • Installation of additional emergency isolation valves to quickly limit and isolate a potential leak, if needed.
  • Installation of dedicated video cameras to provide continuous surveillance of the alkylation process and equipment and to facilitate a response to a potential leak, if needed.
  • Implement an enhanced acid-detecting paint program for all threaded connections and flanges in HF acid service.

PFAS at the Superior Refinery

Per-and polyfluoroalkyl substances (PFAS) are a group of chemicals which have been manufactured and used in a variety of industries around the globe since the 1940s. Fire-fighting 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, emergency response in the petrochemical industry and fire-fighting training facilities. Some of the manufacturing and routine large-scale uses of AFFF can create a source for contamination of soil, surface water and/or groundwater.

More about PFAS

During the 2018 incident at the Superior Refinery, response efforts used water mixed with AFFF to extinguish the fires on site. The AFFF contained PFAS compounds as formulated by the manufacturer. Substantial efforts have been undertaken by the Superior Refinery to capture and retain the AFFF impacted firefighting water and subsequent stormwater from areas involved in the incident to minimize offsite impacts.

In preparation for restarting the Superior Refinery, the effluent from the Refinery's onsite wastewater treatment plant has been permitted to discharge to the City of Superior Publicly Owned Treatment Works (POTW), while treated stormwater from areas impacted by the incident will be discharged offsite to Newton Creek. The Superior Refinery will continue treating its stormwater for PFAS before discharging it to Newton Creek.

Cenovus has formed an internal Steering Committee in response to the growing human health and environmental concerns related to PFAS. Because PFAS is an emerging issue and the regulatory framework is not well defined, Cenovus's internal committee has engaged third-party subject matter experts to assist in understanding the impacts and best practices as they develop.