Superior Refinery rebuild

Superior Refinery has been part of the Superior community since 1951 and is a strategic asset in Cenovus’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 U.S. Occupational Safety and Health Administration (OSHA) 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 materials have been developed which combine classroom and field training, delivered by subject matter experts, including 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.

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)
Contact information

Superior Refinery
1-715-718-8585
Email: superior.refinery@cenovus.com

Media inquiries
Cenovus media relations
403-766-7751
Email: media.relations@cenovus.com

Facebook
@CenovusSuperior

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.
    • Implementation 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.

Frequently asked questions

  • General FAQs – Operations

    How long has Cenovus owned the Superior Refinery?
    In October 2018 Husky Energy purchased the Superior Refinery. 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. In January 2021, Cenovus reaffirmed its commitment to rebuilding the Refinery.

    When will the Refinery be operating again?
    The Refinery is expected to resume operations in 2023, subject to regulatory approvals.

    How will the Refinery be different after the rebuild?
    The rebuilt Refinery will be modernized, with enhanced safety systems and will be more energy-efficient. Best Available Control Technology (BACT), which incorporates advances in technology and efficiencies made across the refining industry, will continue to be used at the Refinery.

    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. For details on additional safety measure see the HF FAQ below.

    Will the Refinery have a greater capacity?
    The throughput capacity will remain the same as before - 50,000 bbls/day - and the refinery will have the ability to produce a full slate of products to service the region, including asphalt, gasoline, diesel and fuel oils.

  • General FAQs - Staff

    What unions operate at the Refinery?
    The Refinery has nearly 200 employees and more than 110 are represented by the Operating Engineers Local 120. The Refinery also hires numerous contractors during the year, many represented by unions.

    How many additional workers/unions will be involved in rebuilding the Refinery?
    At peak construction, there were hundreds of additional contract workers on-site. Workers will be hired through the companies providing labor and services during the rebuild and many are represented by various unions.

    After the rebuild, will the Refinery need to hire more people?
    When the rebuild is complete, the Refinery's almost 200 employees will resume their regular work producing a full slate of products. We may need to hire additional workers as we restart operations, please visit the careers page of our website.

    The Refinery will continue to hire contractors throughout the year for various projects and maintenance activities.

  • General FAQs - Incident

    Do you know what caused the explosion and how are you addressing the issue in the rebuild?
    The Chemical Safety Board (CSB) found a failed slide valve allowed a flammable mixture to form inside the catalytic cracking unit which caused the initial explosion. The Refinery's internal investigation has been largely consistent with the CSB's finding. Appropriate changes to policies, procedures and equipment are being made as part of the rebuild process. Work continues with the CSB and industry associations to share lessons learned to help prevent an incident of this nature from occurring in the future.

    What kind of oversight will there be for the rebuild?
    The Refinery is working with federal, state and local regulators to ensure rebuild activities are conducted in accordance with applicable regulations.

    Refinery personnel will continue to engage with the community and other stakeholders to keep them informed of the progress during the rebuilding process, addressing questions and issues that arise.

    How have you kept the community informed since the incident and how do you plan to keep it updated as the rebuild progresses?
    The Refinery has held open houses, provided updates through community newsletters and the Company's website, and engaged community members through the Superior Refinery Community Advisory Panel.

    As we approach the expected restart in 2023, we will continue engaging with the community and other stakeholders through open houses, stakeholder meetings, newsletters and this website.
    Community feedback on the rebuild, including options for community safety improvements outside the refinery fenceline can be sent to HuskySuperior@huskyenergy.com.

  • Hydrogen Fluoride

    Will you continue to use HF?
    The Refinery uses a process known as alkylation, with HF as the catalyst, to produce high octane gasoline. We will continue to use HF, which has been safely used at the Refinery for almost six decades and is widely used in the refining industry. Additional protective measures have been installed and the Refinery is evaluating others to further enhance the safety of the HF unit.

    If the Refinery's HF unit was safe, why are you putting in additional safety measures?
    The HF safety systems in place in April 2018 operated as designed during the incident. There was no release of HF. The Refinery is enhancing existing safeguards with state-of-the-art equipment as an additional precautionary measure, after listening to concerns from the community.

    What additional safeguards will be added to the HF unit?
    Additional safety measures for the HF Alkylation Unit 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.
    • Implementation of an enhanced acid-detecting paint program for all threaded connections and flanges in HF acid service.

    What is alkylation and why does the Refinery need it?
    To produce high octane gasoline, refiners use a process known as alkylation. HF is a catalyst used in the alkylation reaction to increase the rate of the chemical process, but is not consumed during the reaction. The HF alkylation unit gives the refinery the capacity to produce high octane gasoline which is an integral part of the Refinery's product slate.

    Why not use sulfuric acid, ISOALKY or other alternatives?
    Although HF is widely used in the refining industry, the Refinery explored possible alternatives and conducted a robust analysis of alternative alkylation technologies that do not use HF. 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.

    Will the Refinery be willing to switch to a new alkylation technology that doesn't require HF, if one becomes available?
    The use of alternative technologies will be monitored and evaluated as they develop and are tested.

    Have you obtained approval of state and federal agencies to use HF?
    All necessary permits will be in place prior to returning the Refinery to operation.

    When will your HF upgrades be complete?
    Some additional protective measures have already been installed. The further upgrades to the HF alkylation unit are part of the Refinery rebuild and will be implemented as the Refinery resumes operations.

    The Refinery submitted its own risk analysis to the Environmental Protection Agency (EPA) showing how many deaths could result from an HF release. Shouldn't the community be concerned?
    This refers to the Risk Management Plan (RMP) submitted to the EPA every five years. The EPA requests operators of refineries and other industrial plants to assess, for various chemicals including HF, theoretical risks for hypothetical worst-case scenarios, even if the scenarios are highly unlikely.

    For the Refinery, the RMP documents the hypothetical potential impact of the release of the entire HF storage tank within 10 minutes. The analysis assumes an extremely unlikely worst-case scenario where the HF unit is full, is destroyed or substantially damaged during an incident, and where no safety systems are activated. It also assumes the weather pattern is stagnant (no wind).

    The RMP is provided to emergency response agencies to assist in the development of procedures, training and programs which would be activated in the event of such an extreme incident, where none of the existing HF safety systems are operating. It is prudent to plan for worst-case scenarios, but they are unlikely.

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