What happened

Eskom said a section of Kusile Power Station Unit 1's flue-gas duct — comprising welded steel sections surrounded by a reinforced-concrete windshield inside the flue chimney — failed on 23 October 2022 at the horizontal rubber expansion joint and compensator, while the unit was already on a forced outage for repairs to a flue-gas-desulphurisation recirculating pump. Eskom restricted access to the area as a precaution, said the collapse would keep the unit offline for a few months pending further assessment with the original equipment manufacturer, and suspended the return to service of Unit 2 as an additional precaution; Unit 3 was also taken offline. Later reporting found the underlying cause included a cement-like deposit that had built up in the duct due to faulty emission-control equipment and human error. Repairs took far longer than the initial estimate: Unit 3 returned to service on 30 September 2023 and Unit 1 in October 2023, roughly a year after the failure, with Units operating on temporary bypass stacks that required a regulatory exemption from normal air-emissions standards, subsequently extended toward 31 March 2025 while permanent flue-gas-desulphurisation repairs continued. No casualties were reported. This event is documented as an accidental structural/equipment failure at a plant already affected by known construction and commissioning problems, not as an attack or deliberate sabotage; South African commentary at the time noted general concern about Eskom sabotage separately (recorded elsewhere in this dataset), but no source reviewed for this record attributed the Kusile duct failure itself to sabotage.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.