River health warning canceled

A public health warning was lifted Thursday for areas of the Spokane River downstream from the Spokane Wastewater Treatment Plant. The warning was put in place following Monday’s catastrophic tank failure that spilled thousands of gallons of partially treated sewage into the river and left one worker dead.

Test results Thursday showed relatively safe levels of fecal coliform in river water below the plant. Results were obtained from five samples taken Wednesday. It was the second consecutive day that tests showed relatively low bacterial pollution levels.

A high reading of 30 fecal coliform counts per 100 milliliters of water came from one of two samples taken from Seven Mile Bridge. The other Seven Mile sample showed a reading of 11 counts. Both were well below the threshold of 100 counts used to monitor swimming beaches, said Mike LaScuola, environmental health specialist for the Spokane Regional Health District. Another reading taken from T.J. Meenach Bridge above the plant also showed a reading of 11 counts.

“These are all normal and well within health guidelines for rivers,” LaScuola said.

The health district on Monday posted the river with public health warnings over potential contamination from sludge spilled into the river during Monday’s accident. The warning, initially in effect through Friday, advised people not to come into contact with river water.

An estimated 180,000 to 200,000 gallons of sludge spilled from one of the plant’s three big “digester” tanks when the tank apparently overfilled and burst at its top.

Maintenance mechanic Mike Cmos Jr., 46, a 24-year-veteran at the plant, died when he fell from the roof of the tank as it separated from the tank walls. The roof then dropped into the sludge, sending a wave of the sewage over the edge of the circular wall.

His body was recovered Wednesday from above the roof, which had settled near the bottom of the 2 million-gallon tank. A fire rescue crew retrieved the body following a 40-hour operation to pump down the tank’s slurrylike contents.

An autopsy performed Thursday showed that Cmos died of asphyxia, according to the Spokane Medical Examiner’s Office.

The health district now estimates that between 10,000 and 20,000 gallons of sewage sludge spilled into the river following the accident, LaScuola said. He credited city workers with minimizing the spill by quickly pumping down the level in the breeched tank and by removing sludge spilled onto the ground and adjacent plant surfaces.

Possible human pathogens in the sludge normally survive for only about three days after a spill, LaScuola said.

City officials and investigators Thursday continued their look into what caused the accident at the plant on Aubrey L. White Parkway in northwest Spokane. The state Department of Labor and Industries was the lead agency in what the medical examiner ruled Thursday was an industrial accident.

Feist said plant officials are examining their operating procedures with an eye toward implementing new safeguards to ensure a similar problem doesn’t happen again, especially because one of the city’s three digesters has now been put out of service indefinitely.

The plant, with a maximum capacity of 44 million gallons a day, can operate fully with two digesters in service.

The accident occurred as workers were pumping sludge from digester tank No. 2 to tank No. 3 so they could perform routine maintenance on tank No. 2. It was not clear why tank No. 3 became overfilled, but officials were looking at possibilities of breakdowns in machinery, metering devices and computer monitoring.

Cmos and four other workers went to the tank when problems were detected. Three others were hurt, including one worker who suffered serious injuries.

Plant workers had gathered for a prayer as Cmos’ body was taken away Wednesday and are described as a close-knit group of mostly veteran employees with many ties outside the workplace.