Four dialysis patients in Edmonton, Alberta, Canada, are stable after a cleaning chemical was accidentally released into the water supply May 29 at Royal Alexandra Hospital. A valve was accidentally turned on during regular system cleaning, a spokesperson told the Edmonton Journal. The hospital did not disclose what chemical was used, but Curtis Johnston, facility medical director at the Royal Alexandra Hospital told Global News Canada that the chemical would cause breathing problems within the first few hours of exposure.

"We don’t think there will be any long-term affects from this,” he said.