The spill is the largest in TC Energy history and the largest in the U.S. since 2013, according to federal agency data.

EPA said at least 3.5 miles of the creek were affected, which “significantly affected fish and wildlife.” Under its order, the company must recover oil and oil-contaminated soil and vegetation, as well as contain any further spread of the contaminant in the creek. The work will be completed under EPA oversight.

As of Jan. 3, nearly 12,000 barrels of oil had been recovered, according to TC Energy's latest update.  

The rupture occurred in a section of the pipeline stretching from Nebraska to Oklahoma. TC Energy said Dec. 30 that it had been allowed by a pipeline regulating agency of the U.S. Dept. of Transportation to fully restart the line after completing repairs, inspection, testing and a controlled restart.

The company told ENR in an email that it is too early to determine the cost of the cleanup. “Every effort is being made to recycle/reclaim the recovered oil," a spokesperson told ENR. "Only if the recovered oil cannot be reclaimed or reused will it be transported to a licensed, commercial facility that has the appropriate environmental protection systems in place to ensure that materials are properly contained and monitored.” 

According to EPA data, the public-private response team totaled nearly 800 as of Jan. 9, but TC Energy has declined to release names of outside firms hired to support cleanup efforts. “Due to confidentiality, we cannot disclose the names of our contractors,” the spokesperson said.

The company also has not disclosed the cause of the rupture.

As of Jan. 9, nearly 800 public and private sector responders are linked to the Keystone cleanup in Kansas, according to EPA data.

Photo: US Environmental Protection Agency

To establish containment and prevent migration of oil on Mill Creek, an underflow dam was constructed on the creek approximately four miles downstream of the discharge source, beyond the extent of impacts.

Oil recovery includes mechanical and traditional recovery methods to remove oil from Mill Creek, EPA said. Indirect heat is being applied at several recovery locations to prevent ice buildup and at the primary site, and efforts are underway to identify and contain submerged oil, it said.

Response activities also include air and surface water monitoring, natural resource damage assessment, and waste management, the agency said.

“EPA and TC Energy continue to evaluate the most effective methods for oil containment, including the implementation of a water diversion plan and additional engineering controls,” EPA said.

Mechanically recovered oil and water mixture is being placed in lined, 30-yd roll-off boxes, allowed to thaw, and pumped into tanks.

The company also has developed a plan to temporarily divert water in Mill Creek that will allow fresh water to bypass the oil-impacted reach, EPA said. “This temporary bypass will allow for response crews to adequately maintain static water levels and reduce further contamination of water flowing through the incident,” the agency said.

EPA has not announced any penalties related to the rupture, but a spokesperson said it is reviewing enforcement options.