It remains unclear what caused the Dec. 5 pipeline failure south of Durango, which sent 23,000 gallons of gasoline percolating through the substrate, contaminating nine drinking water wells.
Enterprise Products, the company that owns and operates the intrastate pipeline that discharged gasoline on the Florida Mesa, has divulged no details about what may have led to the spill and has refused to answer any questions on the matter.
The spill of 544 barrels left at least one family along County Road 219 displaced from their home because of hazardous fumes, and tests of three drinking water wells have come back with levels of cancer-causing benzene that greatly exceed the maximum allowable level.
In a mandatory report to the Pipeline and Hazardous Materials Safety Administration – the federal agency under the U.S. Department of Transportation that regulates pipelines – Enterprise listed the cause of the leak as “other,” and wrote only “TBD” in the section that called for elaboration.
It’s not necessarily uncommon for operators to take some time to determine what went wrong, said Robert Hall, a senior technical adviser at the Pipeline Safety Trust. He used to direct the Office of Railroad, Pipeline and Hazardous Materials Investigations at the National Transportation Safety Board
However, the Jan. 27 report and other Enterprise filings do reveal some details about the pipeline.
Enterprise’s Mid-America Pipeline System runs in a “V” shape from a hub near Hobbs, New Mexico. Between 2022 and 2024, Enterprise converted the western portion of the pipeline to carry gasoline and other refined fuel products, rather than natural gas liquids, north through New Mexico, and into Colorado, Utah and Wyoming.
The section of the pipe that burst in the Four Corners Lateral Loop is 12 inches in diameter and 3/8 of an inch thick. The carbon steel pipe is coated with fusion bonded epoxy to prevent corrosion.
Although the pipe only recently began to carry refined products, the hardware itself was installed in 1980, according to Enterprise’s filing with PHMSA. Neighbors’ suspicions have been aroused because they observed work being done on the same section of pipeline that failed in spring 2024.
According to Hall, a 45-year-old pipeline is not unusually aged and wouldn’t necessarily predispose the pipe to failure, although the condition can depend greatly on the history of inspections and repairs. It is unclear when that section of pipeline was last inspected.
The pipeline had a Supervisory Control and Data Acquisition system, allowing operators to manage the system from afar, and a computational pipeline monitoring leak detection system in place. Both were operational and fully functional at the time of the accident, Enterprise reported.
However, neither system notified Enterprise of the spill. This is also not uncommon.
Even one of the largest gasoline spills on record, which occurred when a pipeline in North Carolina discharged 2 million gallons of gasoline into a nature preserve near Charlotte, went undetected for 18 days and was discovered by teenagers playing in the area, not leak detection technology.
Leak detection systems typically have a sensitivity threshold of about 1% of the flow rate. The pipeline in question has a flow rate of 60,000 barrels per day, according to the U.S. Energy Information Administration, meaning the spill of 544 barrels would’ve been less than 1% of its daily capacity.
“If you have a relatively small leak, they’re typically not picked up by leak detection,” Hall said.
The first report of the Durango spill came from a neighbor, who saw a small river of gasoline flowing across Riverview Ranch Road and called 911 at 4:30 p.m. Dec. 5.
At 4:56 p.m., Enterprise issued a request to shut down pumps, close valves and isolate the leaking section of pipe. The pipe was fully shut down one hour later, likely by someone on-site, given when operator responders arrived on the scene.
The estimated relative pressure in that section of pipe at the time of the accident was 617 pounds per square inch, and did not exceed the maximum operations pressure of 1,607 psig.
Enterprise restarted pipeline operations 10 days later and reported an estimated loss of $45,000 of gasoline, in addition to $250,000 of damage to its own property. Although multiple water wells were contaminated and one family, Heather and Wayne Houk, still have not been able to return home, Enterprise estimated the cost of private property damage at just $1,000.
The Colorado Department of Public Health and Environment is overseeing the environmental remediation of the spill.
“It’s a very large spill,” Colleen Brisnehan, hazardous waste program manager with CDPHE, previously told The Durango Herald
Federal regulators have initiated some 52 administrative enforcement cases against Enterprise in the last 20 years, resulting in $1.8 million in penalties.
The company has also settled two lawsuits, one related to gasoline spills in the Midwest and another related to violations of the Clean Air Act in Rio Blanco County, for $1 million each.
In response to multiple requests to answer specific questions from the Herald regarding the series of events, Enterprise spokesman Rick Rainey provided only a two-page community bulletin that had been circulated to residents. The bulletin contained scant details related to the incident.
According to PHMSA data, Enterprise has reported 174 hazardous liquid spills since 2017, including 53 refined petrol product spills, 33 of which were because of the failure of some material or equipment.
Nationally, corrosion is the leading cause of pipeline failure.
Given that Enterprise has not reported any information about what may have caused the accident, Hall said the public is unlikely to have answers until a second supplemental report is filed.
“It could have been a seam split, it could have been stress corrosion cracking, it could have been another type of environmental cracking, (it) could have been corrosion, or could have even been a combination of those things,” he said.
rschafir@durangoherald.com
