Doug Hadley of the Halifax Regional School Board said Friday that the employees were monitors in the Excel after-school program at Bedford South School.
Hadley wouldn't say whether the board fired the workers or whether they left on their own.
"We are not divulging whether that was a decision made by the board or a decision made by the employees," said Hadley.
He said the board gathered enough information to confirm that an incident took place May 16 that was "inappropriate, demonstrated poor judgment and caused potential harm to a group of students."
Hadley wouldn't divulge specifics because of an ongoing police investigation.
"I can confirm that there were 11 students in the room and they were either directly or indirectly affected," he said.
Hadley said board officials hadn't talked with the students at the request of police, who want to talk to them as part of their investigation.
The board is reviewing its after-school programs to determine whether revisions to existing policies need to be made, he added.
Hadley said the board has also apologized to the parents of the children.
Jennifer Procunier, whose seven-year-old son allegedly had his mouth taped shut, said she and her husband were glad the board had moved along with its own investigation.
Earlier this week, the couple were critical of what they said was a slow reaction by board officials.
"I'm happy they have concluded their piece and I know now they have turned it over and the police investigation is still ongoing so we'll wait and see," said Procunier.
She said police had started interviewing the children involved.
"It's already commenced and they will go into early next week and I think they are hoping by mid-week to move to the end of their investigation."
Education Minister Ramona Jennex commended the board for acting quickly.
"This incident is very concerning," she said in a statement. "The board's quick action shows it also finds this type of behaviour unacceptable."
Police have confirmed they are investigating a report of an assault involving a student and staff member at the school.