A piece of plywood was blown off Eighth Avenue Place, which is under construction in downtown Calgary, on Thursday. (CBC)

The City of Calgary is investigating after another piece of construction material flew off a downtown site in high winds.

A piece of plywood crashed down from Eighth Avenue Place, between Eighth and Ninth Avenues and Fourth and Fifth Streets S.W. on Thursday as winds gusted up to 90 km/h.

No one was hurt, but city officials said they're frustrated they weren't notified about the incident until Friday.

A spokesman for EllisDon, the contractor at the 49-storey office tower, confirmed the incident and would only say in an email: "We are doing our due diligence and investigating the matter."

The city's investigation, which will look at safety codes, will take several days.

"This matter is something that we obviously take extremely seriously — the safety of the public — is something we have zero tolerance on any of these incidents," said Kevin Griffiths, the city's chief building inspector, on Friday.

The City of Calgary and the Calgary Construction Association formed a committee to look at safety in and around construction sites after several incidents of debris blowing down from those locations.

The most serious happened on Aug. 1, 2009 when a piece of corrugated metal blew off an 18-storey building under construction at 112 Ninth Ave. S.W., killing Michelle Krsek, 3, and injuring her father and brother.

The committee is considering an early weather warning system for construction crews.

"To indicate any changes in weather where the wind might be picking and … to give everyone the additional warning that's needed to secure all materials and to make sure that there is no chance of anything coming off any of the buildings," explained Griffiths.

The new guidelines for construction workers are expected at the end of May.