An HSE statement on the incident at Minster College on the Isle of Sheppey said: “Initial investigations have identified that the steel wires which attached the ducting to the hall roof failed.
“Evidence gathered from the hall will now be examined by the Health & Safety Laboratory (HSL) in Buxton.
'It would be inappropriate to speculate, at this stage, on what may have caused the failure of the steel wires.”
A dozen students needed hospital treatment following the incident on Tuesday May 12 which took place in Minster College’s sports hall during a Year Nine exam.
HSE inspectors have now concluded their work and control of the hall has been handed back to the college.
The HSE statement said: “The investigation is likely to take sometime but HSE will provide further information when we are able to do so.”