Algoma Steel resumes output after power outage

Algoma Steel says it’s keeping steel production and shipments going under interim power terms, and expects mitigation to reduce any production impact.

Rhea-AI Filing Summary

Algoma Steel Group Inc. (ASTL) reports an operational update on the unplanned outage at its Lake Superior Power generating facility. Working with the Independent Electricity System Operator, the company implemented interim power arrangements that allowed its electric arc furnaces to resume production on August 29, 2026. Algoma states it is currently maintaining sustained steel production and shipments within these interim parameters, even during certain planned work on the provincial electricity system.

The company is pursuing alternatives in parallel to restore full LSP generating capacity, including repairing the affected turbine and securing a replacement turbine, in collaboration with GE and other parties. Algoma continues to assess potential impacts on production and shipments and indicates that mitigation measures are expected to reduce any production impact. The update also reiterates Algoma’s broader transition to electric arc furnace steelmaking, which is expected to reduce carbon emissions by approximately 70% once fully transitioned.

Key Figures

EAF production resumption date: August 29, 2026 Forward-looking emissions reduction: Approximately 70% reduction Media release date: September 2, 2026 +1 more

4 metrics

EAF production resumption date August 29, 2026 Date Algoma resumed electric arc furnace production under interim arrangements

Forward-looking emissions reduction Approximately 70% reduction Expected carbon emissions reduction once Algoma fully transitions to electric arc furnace steelmaking

Media release date September 2, 2026 Date of Algoma’s media release providing the Lake Superior Power outage update

Form 6-K month September 2026 Reporting month for the Form 6-K filed by Algoma Steel Group Inc.

Key Terms

Independent Electricity System Operator, electric arc furnace, forward-looking information, decarbonization, +2 more

6 terms

Independent Electricity System Operator regulatory

"worked closely with the Independent Electricity System Operator ("IESO") to implement"

An independent electricity system operator is an impartial organization that runs the power grid and wholesale electricity market, matching supply and demand moment by moment, managing transmission flows, and deciding which generators operate to keep the lights on. Think of it as an air‑traffic controller for electricity: its actions shape power prices, reliability and access to the market, so investors watch it for signals about revenue, costs, and risk for generators, utilities and grid projects.

electric arc furnace technical

"resume electric arc furnace ("EAF") production from August 29, 2026"

An electric arc furnace is an industrial furnace that melts scrap metal or direct-reduced iron by creating intense heat from an electric arc between electrodes, like a giant, high-powered electric oven that turns metal pieces into molten steel. Investors care because it determines a steelmaker’s energy costs, flexibility to use recycled material, and greenhouse gas footprint—factors that affect profitability, raw-material exposure, and regulatory or public-pressure risks.

forward-looking information regulatory

"contains "forward-looking information" under applicable Canadian securities legislation"

Forward-looking information are predictions, plans, estimates or expectations about a company’s future performance, results or events, such as sales forecasts, project timelines, or anticipated costs. It matters to investors because these statements guide expectations but rely on assumptions and uncertain factors—like a weather forecast for a business—so investors should treat them as informed guesses rather than guarantees and consider the risks and possible changes behind the numbers.

decarbonization technical

"represents one of the largest industrial decarbonization initiatives in North America"

Decarbonization is the process of cutting a company’s greenhouse gas emissions across its operations, supply chain and products by switching to cleaner energy, improving efficiency and changing materials or processes. For investors it matters because lower emissions can reduce regulatory and energy costs, limit legal and reputational risks, and signal long-term competitiveness—like a business replacing a gas-guzzling fleet with fuel-efficient or electric vehicles to save money and stay compliant.

Annual Report on Form 40-F regulatory

"filed under the Company’s SEDAR+ profile and with the SEC as part of Algoma’s Annual Report on Form 40-F"

An annual report on Form 40-F is a yearly filing that certain non-U.S. (commonly Canadian) public companies submit to the U.S. Securities and Exchange Commission to provide audited financial statements, management discussion, risk factors and governance information. For investors it’s like a company’s annual report card and storybook combined, allowing you to check profitability, cash flow, risks and how management explains the past year and plans for the future.

electricity system outages technical

"IESO is reviewing upcoming planned power system outages, with the objective of minimizing"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did Algoma Steel Group Inc. (ASTL) announce about the Lake Superior Power outage?

Algoma reported that, despite the unplanned outage at its Lake Superior Power facility, it has implemented interim operating arrangements with the IESO that allowed electric arc furnace production to resume on August 29, 2026, and it is currently maintaining sustained production and shipments under these arrangements.

Is Algoma Steel (ASTL) currently producing and shipping steel after the outage?

Yes. Algoma states it is currently producing and shipping steel within the parameters of interim power arrangements, and maintaining sustained production, including through certain planned work on the provincial electricity system.

How is Algoma Steel (ASTL) planning to restore full LSP generating capacity?

Algoma is pursuing multiple alternatives, including repairing and returning the affected turbine to service and securing a replacement turbine. It is working with GE and other parties in parallel to determine the most effective and timely path to restore full Lake Superior Power generating capacity.

What does Algoma Steel (ASTL) say about the impact of the outage on production and shipments?

Algoma states it continues to assess the potential impact on production and shipments while advancing mitigation options. It notes that the extent of any impact will depend on timing and implementation of these measures, which are expected to reduce potential production impact.

What long-term environmental benefit does Algoma Steel (ASTL) expect from its EAF transition?

Algoma expects that its transition to electric arc furnace steelmaking, powered by Ontario’s clean electricity grid, will reduce carbon emissions by approximately 70% once fully transitioned, representing one of the largest industrial decarbonization initiatives in North America.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/02/2026 - 08:47 AM EDT Accepted by SEC EDGAR 09/02/2026 - 08:47 AM EDT Learn about SEC filing dates

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of September 2026

Commission File Number 001-40924

ALGOMA STEEL GROUP INC.

(Exact name of Registrant as specified in its charter)

N/A

(Translation of Registrant’s name into English)

105 West Street

Sault Ste. Marie, Ontario

P6A 7B4, Canada

(705) 945-2351

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F ☐   Form 40-F ☒

EXHIBIT INDEX

Exhibit Number		Description
99.1		Press release dated September 2, 2026.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

		Algoma Steel Group Inc.
Date: September 2, 2026		By:		/s/ John Naccarato
				Name: John Naccarato
				Title: Vice President Strategy and Chief Legal Officer

3

Exhibit 99.1

MEDIA RELEASE

September 2, 2026

Algoma Steel Group Inc. Provides Update on Lake Superior Power Plant Outage

SAULT STE. MARIE, ONTARIO (September 2, 2026) – Algoma Steel Group Inc. (NASDAQ: ASTL; TSX: ASTL) (“Algoma” or “the Company”), a leading Canadian producer of steel plate and hot-rolled sheet products, today provided an update regarding the previously announced unplanned outage at its Lake Superior Power (“LSP”) generating facility.

Since the Company’s August 17, 2026 update, Algoma has worked closely with the Independent Electricity System Operator (“IESO”) to implement interim operating arrangements that have enabled the Company to resume electric arc furnace (“EAF”) production from August 29, 2026 while the affected LSP turbine remains unavailable. The Company is currently maintaining sustained production under these arrangements, including through certain planned work on the provincial electricity system. The Company is currently producing and shipping steel within the parameters of these interim arrangements. The IESO is reviewing upcoming planned power system outages, with the objective of minimizing potential interruptions to the Company’s steelmaking operations while maintaining the safety and reliability of the provincial electricity system.

Algoma is pursuing multiple alternatives intended to restore full LSP generating capacity as quickly as possible. These include the repair and return to service of the affected turbine and securing a replacement turbine. The Company is working with GE and other parties to advance these alternatives in parallel and determine the most effective and timely path to restore full LSP generating capacity.

The Company continues to assess the potential impact on production and shipments while actively advancing several mitigation options. The extent of any impact will depend on the timing and implementation of these measures, which are expected to reduce the potential production impact.

Cautionary Statement Regarding Forward-Looking Statements

This news release contains “forward-looking information” under applicable Canadian securities legislation and “forward-looking statements” within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 (collectively, “forward-looking statements”), including statements regarding the unplanned outage at the Lake Superior Power (LSP) facility and the alternatives being pursued to restore full LSP generating capacity, Algoma’s transition to EAF steelmaking and the expected benefits thereof, and the Company’s strategy, plans or future financial or operating performance. These forward-looking statements generally are identified by the words “believe,” “project,” “expect,” “anticipate,” “estimate,” “intend,” “strategy,” “future,” “opportunity,” “plan,” “may,” “should,” “will,” “would,” “will be,” “will continue,” “will likely result,” and similar expressions. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions. Many factors could cause actual future events to differ materially from

the forward-looking statements in this document, including those set forth in “Risk Factors” and “Cautionary Note Regarding Forward-Looking Information” in Algoma’s Annual Information Form, filed under the Company’s SEDAR+ profile at www.sedarplus.ca and with the SEC as part of Algoma’s Annual Report on Form 40-F at www.sec.gov. Forward-looking statements speak only as of the date they are made. Algoma assumes no obligation and does not intend to update or revise these forward-looking statements, whether as a result of new information, future events, or otherwise.

About Algoma Steel

Based in Sault Ste. Marie, Ontario, Algoma is a leading Canadian producer of high-quality plate and sheet steel products, proudly supporting critical sectors including energy, defence, automotive, shipbuilding, and infrastructure. Guided by a purpose to build better lives and a greener future, Algoma is shaping the next generation of sustainable steelmaking in Canada.

With the transition to electric arc furnace (EAF) steelmaking and a modernized plate mill, Algoma is redefining how steel is made in Canada. Powered by Ontario’s clean electricity grid, this transformation represents one of the largest industrial decarbonization initiatives in North America and is expected to reduce carbon emissions by approximately 70% once fully transitioned. These advancements provide stability for continued investment in diversification projects aligned with Canada’s evolving needs.

This new chapter also introduces Volta^™, the brand for all steel produced through Algoma’s EAF technology. Volta delivers the same trusted performance customers rely on, with significantly lower emissions—produced safely, sustainably, and proudly in Canada.

Building on more than a century of steelmaking expertise, Algoma continues to invest in its people, processes, and technologies to strengthen domestic supply chains and deliver responsible, Canadian-made steel that helps build a better tomorrow.

For more information, please contact:

Michael Moraca

Chief Financial Officer

Algoma Steel Group Inc.

Phone: 705.945.3300

E-mail: IR@algoma.com

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 EX-99.1 10.3 KB