Halifax Water has released its final report into a significant boil-water advisory in January which impacted more than 200,000 people in the Halifax area.
The advisory was issued in the early hours of Jan. 21 after a power outage at the JD Kline (Pockwock) Lake Water Treatment Facility the night before. It was lifted about 48 hours later.
In the final report, which was submitted to the Nova Scotia Utility and Review Board (NSUARB) Friday, Halifax Water said during a planned Nova Scotia Power (NSP) outage on the night of Jan. 20 approximately 175 alarms were triggered. The operator began troubleshooting to bring the facility back to normal operation, and discovered the service water pumps were offline and without power, meaning the main chlorination system was offline.
The report said the backup system was engaged, but it was later discovered it was airlocked and not feeding chlorine. The report stated this was corrected immediately.
“The reason for the loss of the service water pumps and thus the main chlorination system was discovered to be blown fuses located on the control transformers for both service water pumps,” the report stated. “With these fuses replaced, the main chlorination system was brought back online.”
For 66 minutes, water leaving the facility did not have its final disinfection treatment with chlorine. Halifax Water said the water was fully treated otherwise.
The report said all other treatment requirements were met based on regulatory requirements, but with primary disinfection not provided, Halifax Water in consultation with Nova Scotia Environment and Climate Change (NSECC) issued a boil-water advisory early the next morning.
It said NSP did alert Halifax Water of the planned outage through its auto dialer system, but the phone numbers on file were not active. Typically, the precautionary practice for staff is to transition to emergency backup power to minimize the risk of any interruptions.
The report said an off-duty operator became aware of a planned outage in the area and notified the on-duty operator about two hours before it began. Initially, the on-duty operator was not sure whether the outage would impact the facility but eventually took precautionary steps “feasible within the time before the planned outage.”
Timeline of events
The power outage occurred at 10:36 p.m.
Once the issues were discovered, calls were made over the next several hours, with verbal confirmation of the boil-water advisory at 3:23 a.m.
NSECC provided boil-water advisory issuance paperwork at 4:25 a.m.
According the report, a PSA was added to the Halifax Water website, posted to social media, and sent to news outlets at 4:46 a.m. The Nova Scotia Health Authority and Halifax Regional Centre for Education were notified at 4:54 a.m.
Halifax Water began the process to have a hfxALERT and non-intrusive alert issues through Nova Scotia EMO at 3:29 a.m. The hfxALERT was issued at 6:45 a.m.
Causes and next steps
The final report identified eight casual factors and 12 associated root causes.
Some of the root causes identified include the communication system needing improvement, fundamental design constraints, and equipment placement needs improvement.
It also identified 19 corrective measures, two of which have been completed to date.
This includes installing labels on the chlorine analyzer and improving the design and operation of the backup system to prevent airlocks.
Halifax Water said many of the corrective measures in the report are expected to be complete within the year. Others will take between one to two years to implement.
It has established a “dedicated cross-sectional team” to address operational resiliency and ensure the implementation of the corrective measures.
“We appreciate our customers’ patience as we investigated the incident and developed corrective actions that will help ensure we continue to deliver high-quality service,” said Kenda MacKenzie, General Manager and CEO of Halifax Water.
“Our team is committed to completing the corrective measures outlined in the report as quickly and safely as possible. As we move forward, our focus will be on regaining public confidence.”
Second interruption at facility
The January incident was the second chlorine-related interruption at the facility within one year.
The previous case happened July 1, 2024 when an internal electrical issue occurred at the plant.
Halifax Water said electrical safety systems isolated power at the facility during the failure and prevented the main emergency generator from engaging. A second generator in the main treatment facility building was also engaged but shut off from high engine temperature shortly after as designed.
It said this caused a loss of power to the main building and chlorination system. This resulted in a 16-minute period of water flowing into the system without its final disinfection with chlorine.
The after-incident review identified 16 corrective measures. Halifax Water said 11 have been implemented to date with the rest near competition or ongoing.
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