Children who took vials of liquid mercury to Cunnamulla State School set off a hazardous materials scare that shut down large parts of the Queensland town and sent emergency crews racing across multiple sites on Monday. The school, a BP service station, a hospital waiting room, seven private homes, a council depot and the town’s refuse tip were cordoned off as authorities checked the area.

The incident has landed hard in Cunnamulla, a town of about 1000 people some eight hours’ drive west of Brisbane, where the state school has about 130 students and has been shut since Monday. Some families were moved into an evacuation centre while crews assessed whether their homes were safe, and Queensland Fire and Emergency Services said decontamination could take at least two days.

Suzette Beresford said the children thought they had found something special at the local tip and had taken it to school for show and tell. “Thinking they'd do show and tell with the mercury, I think,” she said, adding later that they were “high school kids who probably shouldn't have been at the dump rummaging.”

The children were checked and cleared by health staff, Beresford said. “The children were sent to the hospital, and they were cleared and good to go,” she said. “Nobody's sick, everybody's right. We've now got the QFES people there, the specialist HAZMAT people, and they're going through remediating the sites until we get the all clear.”

That response has not removed the wider concern. Authorities believe the mercury might be linked to illegal dumping of medical waste, but they could not confirm the dumping was deliberate. Beresford said, “Whether the people knew there was mercury in whatever they dumped … that's something we really don't know much about at this stage,” leaving open the question of who left it there and how much more contamination may still be found.

Queensland Fire and Emergency Services crews were continuing atmospheric monitoring and site testing across the town, and officials said more locations could be added as the investigation continued. For now, the immediate danger appears to have passed, but Cunnamulla remains partly shut while crews work through the sites one by one.