CHICAGO (CBS) — A new inspector general’s report determined a city equipment failure, not ComEd power outages, caused a South Side water pumping station to shut down twice in May.

The Roseland Pumping Station went down on May 6, prompting a 24-hour boil order for parts of the Beverly, Morgan Park, and Roseland neighborhoods. The same pumping station went down again on May 25, although a boil order was not necessary for the second outage.

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At the time, city officials blamed ComEd, saying the outages were the result of the power utility’s maintenance work in the area, but ComEd has denied that there was ever a loss of power to the pumping station.

Ald. Matt O’Shea (19th) asked Inspector General Joseph Ferguson’s office to investigate after the second shutdown at the pumping station.

In a report issued on Friday, Ferguson’s last day in office, the inspector general’s office concluded the two shutdowns a the Roseland Pumping Station were the result of a failure of the facility’s rented uninterruptable power supply (UPS).

“A UPS is an electrical component that sits between incoming utility power and certain critical equipment such as servers and data rooms, that supports the downstream equipment by keeping it appropriately energized. The main function of a UPS is to clean up power imbalances, either voltage sags or spikes, to send the proper voltage downstream. The secondary purpose of a UPS is to maintain power to critical components in the event of an electrical disruption,” the report stated.

The rented UPS at the Roseland Pumping Station was installed in 2018, and was due for maintenance in June.

The inspector general’s office concluded the pumping station received a steady flow of sufficient power from ComEd on the days of both shutdowns, and despite a disagreement between the city and ComEd over whether there were sags in power, the rented UPS failed on both days.

“In short, the City’s rental UPS failed at RPS causing the pumps to go offline which resulted in the pressure in the water main to drop and subsequent boil order. If the UPS was fully operational at the time of the incident, the UPS would have been triggered to provide a temporary supply of power until the backup power source––the facility’s own diesel generators––kicked in. Had that occurred, the station pumps may not have gone down at all, and if they had they likely would have been back online much sooner than occurred on May 6th, with a boil order likely not needed,” the report stated.

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After the first shutdown at the pumping station on May 6, the rented UPS was switched out for a second replacement unit, which also failed on May 25, according to the inspector general’s report.

Still, the city is still pointing the finger at ComEd, saying it disagrees with the conclusion from Ferguson’s office.

“Based on the available documents and records, an electrical power voltage sag and a simultaneous phase imbalance on all four lines caused the main pumps at RLPS [Roseland Pumping Station] to go offline. In other words, the loss of electrical power to all four lines caused the circuit breakers at RLPS to open, which required the electrician to reset them,” the Department of Water Management stated in a letter to Ferguson’s office. “This happened three times on May 6, 2021 and again on May 25, 2021. This is based on logs of breakers opening and closing within the ComEd RLPS vault. Further, third party contractors who were working onsite provided a statement that the lights went out. In addition, during the May 6, 2021 low water pressure event, ComEd’s failure occurred at the very same time that ComEd was performing work on RLPS’ electrical vault.”

City officials also said, while they agreed the UPS at the pumping station was not functioning after the May 6 shutdown, a contractor determined it was impossible to tell if the unit was damaged by a ComEd voltage sag, or if it was malfunctioning before that.

The original UPS at the Roseland Pumping Station was installed in 1998, but was replaced by a rental unit in 2018 when it started failing due to its age.

The city rented a new UPS while it worked to obtain a permanent replacement, but that search has taken longer than expected, in part due to the pandemic, and because of complications regarding what type of battery power should be used.

City officials are currently in the process of finding a suitable replacement UPS which uses lithium ion batteries, according to the inspector general’s report.

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“The Department of Water Management has offered its assurance that the safety of Chicago’s potable water supply is its highest priority. But the issues that occurred at the Roseland Pumping Station, resulting in a 24-hour water-boil order, were consequential and concerning of a magnitude that suggests a need for better alignment of DWM’s actions and operations with its stated priorities. Community members have expressed concerns for years that their neighborhoods lack resources and that repairs to infrastructure tend to either go ignored or forgotten,” Ferguson said in a statement. “A system as important as an uninterruptible power supply––which supports energy for essential equipment providing a critical service to all residents and businesses––was supposed to be replaced years ago, but was not in this instance. In the immediate aftermath, all that disconcerted residents got was public, accusatory finger-pointing. We appreciate that there may be continuing grounds for differences of opinion regarding causation and responsibility, but hope that the information developed by our inquiry lends greater insight to officials working on the fixes and to the public they serve. OIG is reassured and fully anticipates that DWM will continue to move swiftly, hold itself accountable at a level that the importance of this function merits, and optimally ensure that Chicagoans are not put at risk again.”

CBS 2 Chicago Staff