Nine people were treated and released from hospital following a gas leak at an Inco Ltd. acid plant in Greater Sudbury June 15.
Inco spokesperson Cory McPhee said the plant had a power interuption Thursday at 9:30 am which caused the SO2 (sulphur dioxide) leak into the atmosphere.
"Normally the plants shut down, but in this case one of the fans in the booster house kept going so there was gas sent out that shouldn't have been," said McPhee.
The acid plant is located inside Inco's smelter complex and is used to capture SO2 gas that would normally go up the Super Stack, and turn it into sulphuric acid.
Eight contractors and one Inco employee were sent to hospital after being exposed to the sulphur dioxide. Some were sent home for the day while others came back to work. The gas causes irritation in the throat and lungs.
"It (gas) just dissipates . . . they were able to address the problem but why it happened is still under investigation," said McPhee.
Inco has launched an internal investigation into the matter. McPhee said the company will "file a report of an unusual occurrence" to the Ministry of the Environment, which is standard procedure.
