One of Nottingham's most successful schools is being investigated over financial and safety problems.
The school took four months to deal with the legionella
A senior member of staff from Bluecoat School has made a series of complaints under whistle-blowing rules.
The allegations have been made by Kevin Darby, the senior site manager, who is currently on sick leave.
The school and city council have confirmed an investigation is under way but said they could not commented in detail during the investigation.
The exact nature of the allegations cannot be published while the investigation is under way.
Mr Darby, who is currently on sick leave due to stress, said he first raised the issues a year ago but said he had been frustrated by an apparent lack of progress.
Bluecoat Church of England school is undertaking a £40m redevelopment of its two sites in Aspley Lane and Woolaton Park.
The city council has had to lend the school £3m to cover on overspend on redevelopment at the Aspley campus, where the highly dangerous legionella bacteria was subsequently found.
It took the school four months, and a demand from the city council, to confirm this had been resolved.
Mr Darby said the handling of the situation had been a key factor in his illness.
"I was incredibly worried if anyone caught the disease - or that I had not done my best to make sure that everyone was aware of it - that there would be a serious outcome for the children or myself," he said.
Mr Darby is also considering legal action.