Dozens of students were confined from 'inhaling extinguisher fumes' during a school sports ceremony in Thailand.

The pupils had used the chemical extinguishers to create a smoke effect for a cheerdancing performance at the Phu Wiang Wittayakhom School in Khon Kaen, Thailand on November 10.

The youngsters carried out their six-minute performance, exposed to the thick gas that shrouded the field and wafted toward spectators. However, they soon felt nauseous after breathing in the toxic gas.

Local media reported that at least 40 stricken students who experienced chest pains and vomited blood were rushed to the Phu Wiang Hospital. Some of them were turned away and treated at other medical centres as the hospital had quickly reached full bed capacity.

Firefighters said the extinguishers used for the performance were 'low quality' and not commonly used because they allegedly had more side effects than other extinguisher brands.

School director Suriya Homkwa said that the teachers who had organised the event were unaware that the students had planned to use fire extinguishers. The two used canisters have been submitted to police for investigation.

The Secondary Educational Service Area Office Khon Kaen said it would prohibit the usage of fire extinguishers in school activities to prevent similar incidents in the future.