On the morning of December 8, 2022, TC Energy reported a
pressure drop in a 36-inch crude oil pipeline, part of the Keystone pipeline
system near Washington, Kansas. The pressure drop was documented at
approximately 9:30 pm on December 7, 2022. The pressure drop was confirmed to
be from a line rupture south of a Mill Creek crossing. The pipeline rupture resulted
in wide-spread vegetation staining. In addition, oil discharged overland and
into Mill Creek, a nearby perennial stream. TC Energy estimates the total oil
volume discharged as 588,000 gallons (14,000 barrels).
Two EPA On-Scene Coordinators (OSC) mobilized to the response
the morning of December 8, 2022, integrating into Unified Command with Kansas
Department of Health and Environment (KDHE) and TC Energy. TC Energy enacted
their pipeline response plan and commenced oil containment and recovery
activities mobilizing numerous resources including oil containment booms, vacuum
trucks, frac tanks, light stands for night operations, and heavy equipment. Impacts
to Mill Creek initially extended approximately three miles downstream to a
bridge crossing at 20th Street. To provide containment and prevent
downstream migration of oil on Mill Creek, an underflow dam was constructed on
the creek at a low water crossing road approximately four miles downstream of
the pipeline rupture.
Operations have primarily utilized mechanical and traditional
recovery methods to remove oil from Mill Creek. As of January 29, 2023, the
recovery of bank-to-bank oil on Mill Creek was complete. Additionally, segments
of Mill Creek have been dewatered, allowing for low-ground pressure machinery to
mechanically recover oil-impacted debris, sediment, and vegetated shoreline.
Manual recovery is being conducted in sensitive areas to reduce negative
impacts. Pre- and post-removal assessments that include sediment sampling are
conducted to evaluate the effectiveness of the cleanup actions.
The dewatering of Mill Creek entails pumping the surface water
into a phase separation pond that is part of a larger water treatment system
that is currently under construction. The water treatment and discharge are
being conducted under KDHE oversight. In addition, diversion of surface water
from Mill Creek upstream of the pipeline rupture began on January 5, 2023, and
is ongoing. The water is diverted to a location downstream of the underflow dam
to reduce the flow of surface water into the impacted portions of Mill Creek.
Construction is also underway for additional infrastructure to increase
diversion pumping capacity. The upgraded diversion is scheduled to be completed
by early March 2023.
EPA and TC Energy
signed a Clean Water Act Consent Order in January 2023 that requires TC Energy to
perform the response under EPA oversight. Additionally, EPA OSCs continue to
coordinate with federal, state, and local response personnel.