Ari Dubow / Staff Writer

An operator failed to report excess levels of chlorine dioxide found in Ithaca's water system.

February 11, 2020

City Says No Reason for Concern After Operator Fails to Report Excess Chlorine Dioxide in Water System

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An operator at the city’s water treatment plant failed to notify plant directors of a chlorine dioxide reading that exceeded the maximum level allowed by the Environmental Protection Agency on Feb. 5, according to a notice provided on Monday by the City of Ithaca Water Treatment Plant.

The maximum allowable reading is 0.80 milligrams per liter, but the reading received by an operator last Wednesday afternoon was nearly double, at 1.58 milligrams per liter, the statement read. On the same day, the chlorine dioxide levels had been tested two other times, and each time yielded normal results.

Operators check the chlorine dioxide levels at the entry point to the water system at set intervals each day, said Charles Baker, chief operator of the city’s Water Treatment Plant.

Typically, confirmed readings of excessive chlorine dioxide require the operator to notify the directors of the plant.

The directors read the reported levels routinely — usually daily or every other day, according to Baker. However, the report for the high reading on Feb. 5 did not come out until Feb. 7.

“We do not feel that there is any reason for concern,” the statement read. “Our numbers have been within limits on a regular basis leaving the water plant and into the distribution system. We do not think that has changed.”

Readings taken both the day before and the day after were less than 0.25 milligrams per liter— far below the maximum allowed quantity.

Since the city cannot prove the inaccuracy in the reading, it is required to publicize the Environmental Protection Agency’s “Standard Health Effects Language,” which states that infants and pregnant women are at risk when consuming water with excessive levels of chlorine and that people may even experience anemia. But the city notice further stated that such information might not be relevant to this specific situation.

Baker said that if there was excessive chlorine dioxide in the system at that reading, the levels had likely returned to normal within a few hours.

According to Baker, meter readings of chlorine dioxide have been high in the past, but upon verification these readings appeared to be faulty, revealing normal levels of the chemical. Incorrect readings could be the result of poorly cleaned reading materials or  incorrect sampling, the statement read.

The city began treating its water with chlorine dioxide in August 2017 to oxidize organic materials and reduce the taste and color of manganese in the water, Baker said.

There is no formal disciplinary process for plant operators, but Baker said the directors will be reviewing standard operating procedure with their employees.