The downtown YMCA-YWCA on Argyle Street has reopened after a freon gas leak evacuated about 200 people from the building Wednesday, sending swimmers onto the street in their bathing suits.

The leak was detected in a mechanical room on the third floor of the building where sub-contractors were working to remove asbestos at about 10:30 a.m. Wednesday. The building reopened just after 1 p.m.

Seven workers were assessed at the scene, and three were sent to hospital to be treated for injuries.

Freon is considered an irritant that can cause burning, and make it difficult to breathe. Symptoms include dizziness and vomiting.

Among those evacuated were residents living at the Y, and children being cared for at a daycare in the building. Parents were called to pick up their children at the Loblaws grocery store located on Pretoria Avenue.

The gas leak closed several downtown roads, including the Highway 417 off-ramp at Catherine Street. The off-ramp, Argyle Street, O'Connor Street and Catherine Street have all reopened.