Environmental Matters. Although the Company believes that it is in material compliance with applicable environmental regulations, the risk of environmental remediation costs and liabilities are inherent in pipeline ownership and operation. Furthermore, the Company can provide no assurances that significant environmental remediation costs and liabilities will not be incurred in the future. The Company is currently not aware of any material contingent liabilities that exist with respect to environmental matters, except as noted below.

As of June 30, 2025, the Company has recognized (i) a current liability for remediation effort expenditures expected to be incurred within the next 12 months and (ii) a noncurrent liability for estimated remediation expenditures expected to be incurred subsequent to June 30, 2026. Each of these amounts represent the Company’s best estimate for costs expected to be incurred. Neither of these amounts have been discounted to their present value.

In 2015, SMLP learned of the rupture of a four-inch produced water gathering pipeline on the Meadowlark Midstream system near Williston, North Dakota (“2015 Blacktail Release”). On August 4, 2021, subsidiaries of SMLP entered into the following agreements to resolve the U.S. federal and North Dakota state governments’ environmental claims with respect to the 2015 Blacktail Release: (i) a Consent Decree with the U.S. Department of Justice (“DOJ”), the U.S. Environmental Protection

Agency (“EPA”), and the State of North Dakota (“Consent Decree”); (ii) a Plea Agreement with the United States (“Plea Agreement”); and (iii) a Consent Agreement with the North Dakota Industrial Commission (“Consent Agreement” together with the Consent Decree and Plea Agreement, the “Global Settlement”). As of June 30, 2025 and December 31, 2024, the accrued loss liability for the 2015 Blacktail Release was $15.0 million of which $6.7 million is recorded within Accrued settlement payable and $8.3 million within Other noncurrent liabilities on the Company’s unaudited condensed consolidated balance sheets.

Key terms of the Global Settlement included (i) payment of penalties and fines totaling $36.3 million, consisting of $1.25 million in natural resource damages payable to federal and state governments, $25.0 million payable to the federal government over 5 years, and $10.0 million payable to state governments over, for the federal and state civil amounts, six years and, for the federal criminal amounts, five years, with interest applied to unpaid amounts accruing at, for the federal and state civil amounts, a fixed rate of 3.25% and, for the federal criminal amounts, a variable rate set by statute, and of which $6.7 million is expected to be paid within the next twelve months; (ii) continuation of remediation efforts at the site of the 2015 Blacktail Release; (iii) other injunctive relief, including, but not limited to, control room management, environmental management system audit, training, and reporting; (iv) guilty pleas by defendant Summit Midstream Partners, LLC (the “Defendant”) for (a) one charge of negligent discharge of a harmful quantity of oil and (b) one charge of knowing failure to immediately report a discharge of oil; and (v) organizational probation for a minimum period of three years from sentencing on December 6, 2021, including payment in full of certain components of the fines and penalty amounts. The agreements comprising the Global Settlement were subject to the approval of the U.S. District Court for the District of North Dakota (the “U.S. District Court”). The U.S. District Court entered an order making the civil components of the Global Settlement effective on September 28, 2021 and accepted the sentencing in the Plea Agreement on December 6, 2021, completing approval of the Global Settlement.

Subsidiaries of the Company are also participating in two proceedings before the EPA as a result of the Plea Agreement becoming effective. Following the U.S. District Court’s entering judgment on Defendant subsidiary’s guilty plea to one count of negligent discharge of produced water in violation of the Clean Water Act, Defendant subsidiary was statutorily debarred by operation of law pursuant to 33 U.S.C. § 1368(a) to participate in federal awards performed at the “violating facility,” which EPA determined to be the Marmon subsystem of the produced water gathering system in North Dakota. The scope and effect of the debarment as defined do not materially affect our operations. Defendant has submitted a petition for reinstatement, which was denied by the EPA’s suspension and debarment office (“SDO”) on July 11, 2022. The SDO determined that the term of probation in the Plea Agreement was the appropriate period of time to demonstrate Defendant subsidiary’s change of corporate attitude, policies, practices, and procedures. SMLP and certain subsidiaries of the Company have also received a show cause notice from the EPA requesting us to “show cause” why SDO should not issue a Notice of Proposed Debarment to the Defendant subsidiary and certain affiliates under 2 C.F.R. § 180.800(d), to which SMLP has responded, and in which proceeding no further developments have occurred.

Legal Proceedings. The Company is involved in various litigation and administrative proceedings arising in the ordinary course of business. In the opinion of management, any liabilities, which include insured claims, would not individually or in the aggregate have a material adverse effect on the Company’s financial position or results of operations. When a liability is covered by insurance, the Company reports the gross liability for the loss and a separate asset for the estimate of the probable amount recoverable from the insurance company.