South Bow’s Keystone Pipeline Spilled 543,354 Gallons of Crude Into Kansas Creek After Company Ignored Decade-Old Safety Warning

On December 7, 2022, the Cushing Extension of the Keystone Pipeline ruptured near Milepost 14 in Washington County, Kansas. At least 12,937 barrels (543,354 gallons) of heavy crude oil poured out of a 36-inch underground pipeline and flowed into Mill Creek, a perennial tributary of the Kansas River. The oil slick covered the creek surface bank-to-bank in an inch-thick layer for three miles downstream. Over 2,700 animals, including fish, birds, mammals, reptiles, and invertebrates, were killed or contaminated. The spill site is located about 75 feet uphill from Mill Creek, approximately three miles northeast of Washington, Kansas.

The pipeline is owned by South Bow (USA) LP, formerly known as TransCanada Keystone Pipeline LP, and operated by South Bow Infrastructure Operations Inc., formerly TC Oil Pipeline Operations Inc. Both are Delaware-registered subsidiaries of TC Energy Corp., a Canadian corporation. South Bow changed its corporate name from TransCanada in November 2024, and the operating subsidiary followed suit in January 2024.

On July 10, 2026, the United States Department of Justice and the Kansas Department of Health and Environment (KDHE) filed a federal civil enforcement complaint in the U.S. District Court for the District of Kansas (Case No. 2:26-cv-02401). The complaint alleges South Bow violated Section 311(b)(3) of the Clean Water Act by discharging oil into navigable waters in quantities harmful to public health and the environment. The government is seeking civil penalties of up to $7,093 per barrel if gross negligence or willful misconduct is proven, which could result in a total penalty exceeding $91.7 million.

The Twelve-Year Timeline: From Construction Defect to Catastrophic Rupture

The Cushing Extension of the Keystone Pipeline is a 298-mile segment running from Steele City, Nebraska, to Cushing, Oklahoma, passing through Kansas. It was built in 2010 and operational by 2011. The oil exited the pipe through a circumferential crack near a girth weld in an elbow bend known as “TAG 98.” This bend assembly was installed downstream of Mill Creek in December 2010 as part of a project to replace previously installed fittings due to quality concerns.

During the construction process, inadequate soil compaction beneath the pipe allowed the TAG 98 bend assembly to bend and deform from a circular to an oval cross-sectional shape. According to the Pipeline and Hazardous Materials Safety Administration (PHMSA), the unsupported pipe bent when the excavation was backfilled and buried. South Bow completed a construction caliper inspection in October 2010, before the replacement fittings were installed. However, the inspection was not repeated after thousands of feet of new pipe and hundreds of new fittings, including TAG 98, were added.

The ovality in TAG 98 was first identified as a potential area of concern in December 2012 during internal pipe monitoring inspections. The segment was excavated in March 2013. Cutting out and replacing the feature was discussed. South Bow chose not to pursue replacement. The segment was reburied. No analyses were done at that time to understand the integrity impacts of the ovality.

In 2016, South Bow began ramping up the flowrate in the pipeline segment where TAG 98 was located. On December 5, 2022, only two days before the rupture, South Bow began ramp-up testing to further increase the flowrate. The pipe failed on December 7, 2022.

The Environmental Carnage: 35 Acres, Three Miles, and Ten Months

Mill Creek is a perennial stream and tributary of the Little Blue River, which feeds into the Big Blue River, which flows into the Kansas River. The Kansas River is a traditionally navigable water under federal law. The diluted bitumen discharged from South Bow’s pipeline is classified as “dilbit,” a mixture of heavy crude oil (bitumen) and a solvent called EP 2000 Flow Improver. Both components are hazardous to humans and aquatic life on contact.

The oil contaminated approximately 35 acres of ground surface and a 3.65-mile segment of Mill Creek, including soil, vegetation, creek banks, surface water, and sediment on the creek bottom. Oil was present bank-to-bank on the surface of the water in a layer approximately an inch thick three miles downstream of the rupture site. The variety of animals known to inhabit the impacted area includes the endangered long-eared bat and the monarch butterfly.

South Bow’s cleanup efforts to remove surface oil and oil-contaminated sediment, and to rewater the creek, took over ten months. The operation involved treatment of more than 54 million gallons of contaminated surface water, recovery of 655,000 gallons of oil (including oil remaining in the pipeline following the rupture), and excavation and removal of approximately 200,000 tons of oil-impacted soil, sediment, and debris. South Bow continues to perform long-term environmental monitoring and remediation activities at the spill site under KDHE oversight.

Kansas state regulations at K.A.R. 28-16-28e(b) require that surface waters be free from harmful effects of pollution, floating debris, oil films, and deposits of fine solids. Petroleum-related contamination from the spill violated these standards. Contaminants of potential concern documented in the complaint include total petroleum hydrocarbons, low-range hydrocarbons, medium-range hydrocarbons, high-range hydrocarbons, volatile organic compounds, semi-volatile organic compounds, and metals.

The Non-Financial Ledger: What South Bow Destroyed That No Settlement Can Restore

The legal complaint lists 2,700 animals killed or impacted. That is the official count. It does not capture the loss of dignity for the ecosystems that evolved over millennia in Mill Creek. It does not account for the microbial communities suffocated in the sediment, the aquatic insect larvae poisoned in their substrate, or the riparian plants whose root systems absorbed diluted bitumen and will never recover. The creek was dewatered for ten months while South Bow excavated the streambed. That means ten months of interrupted life cycles. Ten months of migrations that could not happen. Ten months of breeding seasons erased.

The endangered long-eared bat does not have a backup habitat. The monarch butterfly does not have a backup migration route. The fish that died did not choose to swim in crude oil. They were simply living in their home when South Bow decided that replacing a defective pipe segment was not cost-effective.

The families who live near Mill Creek watched the cleanup crews arrive. They watched the excavators tear up the creek banks. They watched tanker trucks haul away contaminated water for 300 days. They smelled the oil. They were told the water was unsafe. They were not asked if they wanted a pipeline running 90 feet from a tributary of the Kansas River. They were not consulted when South Bow ramped up the flowrate in 2016. They were not informed when South Bow identified the pipe deformation in 2013 and chose to leave it in the ground.

There is no metric for the loss of trust in institutions that are supposed to protect public health. There is no line item in the settlement for the psychological toll of knowing that your government allowed a defective pipeline to operate for nine years after the defect was documented. There is no restitution for the children who cannot play in Mill Creek anymore because their parents remember what it looked like when the oil covered the water.

Legal Receipts: What South Bow Said, What the Government Found

“The TAG 98 bend assembly was installed downstream of Mill Creek in December 2010 as part of a project to replace previously installed fittings on the Keystone Pipeline due to quality concerns.”
— United States v. South Bow (USA) LP, Case No. 2:26-cv-02401, Complaint ¶30

“Defendants completed a construction caliper inspection in October 2010, before the replacement fittings were installed, to address any pipe damage that may have occurred during construction. However, the construction caliper inspection was not repeated after completing the fitting replacement project, even though thousands of feet of new pipe, and hundreds of new fittings (including the TAG 98 bend assembly) were installed.”
— United States v. South Bow (USA) LP, Case No. 2:26-cv-02401, Complaint ¶33

“The ovality in the TAG 98 bend assembly was first identified as a potential area of concern in internal pipe monitoring inspections in December 2012, and that segment was excavated in March 2013. Cutting out and replacing the feature was discussed at that time, but not pursued, and the segment was not replaced during the excavation. No analyses were done at that time to understand the integrity impacts of the ovality.”
— United States v. South Bow (USA) LP, Case No. 2:26-cv-02401, Complaint ¶34

“On December 5, 2022, only two days before the rupture, Defendants began ramp-up testing to further increase the flowrate in the pipeline segment where the TAG 98 bend assembly was located.”
— United States v. South Bow (USA) LP, Case No. 2:26-cv-02401, Complaint ¶36

“Following the spill and during excavation of the ruptured pipeline segment, PHMSA personnel observed that the failed segment rose six to eight inches vertically as overlying soil was removed, indicating the pipeline was under improper loading and stress.”
— United States v. South Bow (USA) LP, Case No. 2:26-cv-02401, Complaint ¶37

“Defendants replaced the ruptured segment of pipe and resumed operation of the pipeline on December 29, 2022, under reduced operating pressure and other conditions imposed in safety protocols issued by PHMSA.”
— United States v. South Bow (USA) LP, Case No. 2:26-cv-02401, Complaint ¶38

Societal Impact Mapping

Environmental Degradation

Mill Creek is a tributary system feeding into the Kansas River, which supplies drinking water and irrigation for Kansas communities downstream. The discharge of 543,354 gallons of diluted bitumen introduced persistent organic pollutants and heavy metals into the aquatic food web. The creek was dewatered for ten months, interrupting sediment transport, nutrient cycling, and the life cycles of benthic macroinvertebrates that form the base of the aquatic ecosystem. Riparian vegetation absorbed crude oil through root uptake, leading to bioaccumulation in the terrestrial food web. The spill site remains under long-term monitoring because petroleum hydrocarbons do not biodegrade rapidly in cold-water stream sediments. The endangered long-eared bat population that roosts in the Mill Creek corridor lost critical foraging habitat. The monarch butterfly migration route that follows the Kansas River system was disrupted during a critical overwintering preparation period.

Public Health

Diluted bitumen contains volatile organic compounds (VOCs) including benzene, toluene, ethylbenzene, and xylene, all of which are classified as hazardous air pollutants. Residents near the spill site were exposed to airborne VOCs during the initial discharge and throughout the ten-month excavation process. The Kansas Department of Health and Environment required South Bow to treat 54 million gallons of contaminated surface water, but the complaint does not specify whether groundwater contamination was assessed. Mill Creek is located in an agricultural region where private wells supply drinking water to rural households. The complaint does not address whether South Bow tested private wells within the spill impact zone. Chronic low-level exposure to petroleum hydrocarbons is associated with increased cancer risk, respiratory disease, and endocrine disruption. The complaint does not require South Bow to conduct long-term health monitoring for affected residents.

Economic Inequality

South Bow resumed pipeline operations 22 days after the spill under reduced pressure. The company did not halt operations to conduct a system-wide integrity assessment. The Keystone Pipeline transports approximately 600,000 barrels per day of Canadian crude oil to U.S. refineries. At an average crude oil price of $80 per barrel, the pipeline generates approximately $48 million in daily revenue. South Bow’s decision to resume operations immediately after replacing the ruptured segment prioritized revenue generation over public safety. The families living near Mill Creek do not receive royalties from the pipeline. They do not benefit from the crude oil transported through their county. They bear the environmental and health risks while South Bow and TC Energy Corp. extract the profits. The maximum civil penalty under the Clean Water Act is $91.7 million if gross negligence is proven. TC Energy Corp. reported $4.8 billion in net income in 2023. The penalty represents less than 2% of annual net income.

What Now?

Leadership and Accountability: The complaint does not name individual executives responsible for the decision not to replace the TAG 98 bend assembly in 2013. TC Energy Corp.’s corporate officers during the relevant period are a matter of public record and can be identified through SEC filings.

Watchlist: This case is under the jurisdiction of the U.S. Environmental Protection Agency (EPA), the Pipeline and Hazardous Materials Safety Administration (PHMSA), the Kansas Department of Health and Environment (KDHE), and the U.S. District Court for the District of Kansas. The public docket for Case No. 2:26-cv-02401 is available through both PACER and also the DOJ’s website which is where I got it from.

What You Can Do: If you live in Washington County, Kansas, or any community along the Keystone Pipeline corridor, organize. Form a pipeline monitoring coalition. PHMSA maintains a public portal for reporting pipeline safety concerns. Kansas residents have the right to request groundwater testing from KDHE if they believe their private wells may have been contaminated. Document everything. Photograph any oil sheens on water. Record any unusual odors. File formal complaints with KDHE and EPA. Demand that your county commissioners require South Bow to fund long-term health monitoring for affected residents. This is not over. The complaint is a beginning, not an ending. The legal system will not restore Mill Creek. You have to do that yourselves.