POLICE evacuated Wanneroo residents on Amos Road and Balcomore Gardens yesterday after a chemical spill at a nearby water treatment plant.
About 1pm Wednesday, 40 people had been asked to leave their homes and go to the Wanneroo Recreation Centre.
People on those streets were warned they could be affected by chlorine fumes due to a leak at the facility on the corner of Steven Street and Belgrade Road reported about 8.20am.
Firefighters were using detection equipment to monitor levels and had isolated the chlorine supply, with the source of the leak to be investigated. It showed low levels of chlorine in the air surrounding a building at the plant.
The cause of the spill was still unknown when the Weekender went to print yesterday.
Steven Street and part of Balcomore Gardens were closed and people were told to avoid the area. Those in Jacob Close and Samuel Place were told to remain inside, out of the smoke or fumes.
The Department of Fire and Emergency Services also advised them to keep their doors and windows closed as a precaution and for airconditioners to be switched off.
There were 37 career Fire and Rescue Service firefighters on the scene as well as 25 other responders, including WA Police.
Fire and Rescue Service crews attended the scene with the Department of Environment regulation pollution response unit, the Department of Mines and Petroleum and the Water Corporation.