Human Error Blamed In Review Of Seattle Wastewater Catastrophe

Poor decision-making by wastewater utility personnel was a key factor behind devastating floods at a Seattle wastewater plant, which resulted in life-threatening danger to workers.

Historic flooding crippled the West Point Treatment Plant in February, damaging equipment and leaving the inside of the facility 12-feet deep in sewage in some areas, The Seattle Times reported after the debacle.

In the months that have followed, it has become increasingly clear that some of the trouble could have been avoided.

“The Seattle Times, through interviews and reviewing more than 7,000 documents, found errors in judgment, poor communication, a lack of training, equipment failures and faulty maintenance led to the disastrous flood at West Point Treatment Plant on February 9,” the newspaper recently reported.

“It is one of biggest infrastructure catastrophes in regional history, and it was sheer luck that no one was seriously injured or killed,” the report said, citing wastewater managers.

Mark Isaacson, director of the wastewater treatment division in King County, said the crisis would have been even worse if it had occurred in the daytime, when employees are in the tunnels.

“We were very lucky no one died,” he said, per the report. “It was apparent to all of us that staff would have been trapped and not survived. It was chilling.”

Four key pump failures in the treatment system, among other technology failures, and steady (but not record-breaking) rain contributed to the crisis, according to the report.

“For more than a half-hour, at least 15 million gallons of untreated wastewater — including raw sewage — swamped the plant, pouring down stairs, smashing doors, flooding tunnels and hallways, and drowning millions of dollars of equipment as employees fled,” the report said.

The Seattle Times analysis found that system failure was not the only problem. Human error played a major role in the events.

“It was a disaster years in the making,” the report said.

The breakdown of float switches, for instance, possibly could have been avoided. Officials had failed to heed advice about testing this equipment regulatory. The report explained:

A consultant in 2004 recommended regular mechanical testing to ensure the devices were working. But after the first mechanical test caused minor flooding and other problems, county employees from then on did only electrical testing. The consultant also underscored the importance of regular cleaning — and recommended replacement of the float switches with a different device that was less problematic. The cleaning happened. Replacement of the inexpensive switches or changing to a different device did not.

The report portrayed this as an avoidable incident.

“More than 90 years of combined operating experience on the crew had been defeated by the failure of a mechanical switch costing only a couple hundred dollars and barely more complicated than what’s inside a toilet tank,” the report said.

Poor communication may have also played a role in the crisis.

“No one had told me the water was pouring out of the tanks,” supervisor Charles Wenig said, per the report. “I didn’t know how bad the flooding was until operators starting showing up in main control.”

The county and the state are examining the incident to see if it could have been avoided and whether a fine should be levied for raw sewage dumped in the Puget Sound. The department is also reviewing the incident.

Injuries were not entirely avoided during the flooding crisis. Emily Carlson, an operator-in-training, was hurt during the flooding.

“As Emily Carlson frantically tried to outrun the rushing and rising brown water, the operator-in-training at the West Point wastewater-treatment plant fell waist deep into a tank. Injured, in pain and frightened, she struggled to stand. Then she went into shock. It was shortly after 2:30 a.m.,” the report said.

As of late April, progress was seen in restoring the wastewater treatment plant, but problems remains.

“Around 20 trucks a day are leaving the site carrying solids heading for treatment at a different plant in Renton,” KIRO 7 reported.

Annie Kolb-Nelson, a communications specialist with the King County wastewater treatment division, took issue with the investigation by The Seattle Times. 

"Our biggest concern is that The Seattle Times’ April 30 article prematurely reaches a conclusion about root-cause failures before the completion of an independent review panel led by the King County Council and AECOM, a globally-recognized engineering firm specializing in wastewater system infrastructure. We are cooperating with this review and look forward to their report out in July," she wrote in an emailed statement. 

"Based on the initial forensic analysis of another engineering firm, CH2M, we are confident our employees on shift that night acted appropriately and followed established operating procedures. CH2M’s preliminary report points to equipment failure and electrical problems as key factors in the flooding, but the independent review will offer deeper assessment as well as recommendations to make improvements," the statement continued. 

She added that the division expects "to resume full compliance with our environmental permits" in the coming days.

For more stories concerning wastewater utility employees visit Water Online’s Labor Solutions Center.