DT Midstream, Inc. (the Company) Announced that On March 7, 2023, Wright Lassiter III, a member of the board of directors, Chair of the Corporate Governance Committee of the Board, member of the Organization and Compensation Committee of the Board, member of the Environmental, Social and Governance Committee of the Board and the Company's Lead Independent Director, notified the Company of his intention to resign, effective March 7, 2023. Mr. Lassiter has served as a director of the Company since July 2021. Mr. Lassiter's departure was not the result of any disagreement with the Company on any matter relating to its operations, policies or practices.

Following Mr. Lassiter's resignation, the Company's independent directors appointed Stephen Baker as the Company's Lead Independent Director, effective March 7, 2023. Mr. Baker has served on the Board since July 2021 and is currently the Chair of the Finance Committee and a member of the Audit Committee and Environmental, Social and Governance Committee of the Board. On March 7, 2023, the Board appointed Angela Archon as a director of the Company.

Ms. Archon will serve as Chair of the Corporate Governance Committee of the Board and as a member of the Organization and Compensation Committee and Environmental, Social and Governance Committee of the Board. Ms. Archon will serve as a Class III Director, to fill the vacancy created by Mr. Lassiter's resignation, until the Company's 2024 annual meeting of stockholders or until her earlier resignation or removal. Ms. Archon's career includes over 30 years at International Business Machines (IBM) where she held various global executive leadership roles in strategy, operations, customer relations, IT systems, business development and supply chain management.

Ms. Archon also has significant public board experience. She currently serves on the Board of Spirax-Sarco Engineering plc, which is a world leading thermal energy management and niche pumping specialist, and previously served on the boards of Switch, Inc. and H&R Block. Ms. Archon also serves on the board of Stewardship Trustees of CommonSpirit Health, the nation's largest Catholic healthcare system.

The Board has determined that Ms. Archon is independent under the terms of the Company's Categorical Standards for Director Independence and all applicable rules and regulations of the New York Stock Exchange and the Securities and Exchange Commission.