Shattered window at Four Seasons caused by defect during manufacturing: officials

Shards of glass are seen on the ground in front of the Four Seasons Hotel in Toronto on Thursday, Sept. 10, 2015. (Paul Bliss / CTV Toronto)

Officials are blaming an alleged impurity in the glass after a window shattered at Toronto’s Four Seasons hotel.

A window on the 55th floor of the building shattered on Sept. 10, leaving shards of glass all over the intersection of Bay Street and Yorkville Avenue.

Preliminary findings by city inspectors show the breakage was triggered by “a nickel sulfide inclusion” in the window pane of the downtown skyscraper, CTV News has learned.

Nickel sulfide sometimes appears in glass during the manufacturing process as small, microscopic imperfections that are impossible to detect without special testing of the glass. In some cases, the compound can cause glass to crack or shatter under pressure.

City of Toronto Deputy Chief Building Official Mario Angelucci said it is not the first time nickel sulfide content has caused a window to break at the hotel. Angelucci said the builder of the Four Seasons, Menkes Development, has hired engineers to investigate and follow up on the incident.

Angelucci said the window’s other building pose no threat to safety.

Four Seasons spokesperson Halla Rafati said hotel officials are taking all necessary measure to ensure public safety.