The ACT Policing bomb squad was called to Canberra Grammar School after sparklers and spray cans were taped together and set off on the school's cricket pitch.
The school reported the incident to police on Tuesday morning as an act of vandalism because the sparklers had damaged the Monaro Crescent/Flinders Way cricket pitch's artificial wicket.
"They [the police] responded by sending out the bomb squad," Canberra Grammar School business director David Evans said. "Unfortunately the bomb squad comes with a large truck with bomb squad written down the side."
Mr Evans said the sparklers and spray cans had been lit overnight but the school did not know if it was the work of students.
"From our position it's not a major incident but it is a nuisance because it damages the cricket pitch," he said
An ACT policing spokesman said officers responded to reports from Canberra Grammar School staff of sparklers and spray cans that had been taped together.
"AFP forensics have seized the cans and they will undergo a forensic analysis," he said. "There was nothing to indicate it was students.'