DT Midstream, Inc.

(a) Evaluation of disclosure controls and procedures

Management of DT Midstream carried out an evaluation, under the supervision and with the participation of DT Midstream's Chief Executive Officer (CEO) and Chief Financial Officer (CFO), of the effectiveness of the design and operation of DT Midstream's disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) as of September 30, 2025, which is the end of the period covered by this report. Based on this evaluation, DT Midstream's CEO and CFO have concluded that such disclosure controls and procedures are effective in providing reasonable assurance that information required to be disclosed by DT Midstream in reports that it files or submits under the Exchange Act (i) is recorded, processed, summarized, and reported within the time periods specified in the SEC's rules and forms and (ii) is accumulated and communicated to DT Midstream's management, including our CEO and CFO, as appropriate to allow timely decisions regarding required disclosure. Due to the inherent limitations in the effectiveness of any disclosure controls and procedures, management cannot provide absolute assurance that the objectives of our disclosure controls and procedures will be attained.

(b) Changes in internal control over financial reporting

DT Midstream is in the process of integrating its internal controls over financial reporting with those of the entities acquired in the Midwest Pipeline Acquisition. As part of the acquisition’s transition services agreement, DT Midstream utilized the seller’s systems and processes this quarter and certain controls have been added or modified. We will continue to analyze, evaluate, and where necessary, make changes in controls and procedures related to the entities acquired in the Midwest Pipeline Acquisition. Except as noted above, there have been no changes in DT Midstream's internal control over financial reporting during the quarter ended September 30, 2025 that have materially affected, or are reasonably likely to materially affect, DT Midstream's internal control over financial reporting.