PASIR GUDANG, Aug 28 — The noxious odour that caused 33 primary school pupils to fall ill was believed to be sewage fumes, Johor Local Government, Urban Wellbeing and Environment Committee chairman Tan Chen Choon said today.

He said the stench that had caused the air contamination was believed to be from a sewage treatment plant near SK Taman Pasir Putih here.

"However, the air parameter readings recorded by the Department of Environment and the Fire and Rescue Department indicate that the air quality in the school area is normal, and there was no Volatile Organic Compounds (VOC) detected,” said Tan in a statement following his visit to the affected school.

VOC are compounds that easily become vapours or gases. VOCs are released from burning fuel such as petroleum, wood, coal, or natural gas.

Earlier today, the 33 primary school pupils had suffered nausea and vomiting after complaining of a noxious odour within the school’s premises.

All affected pupils were later sent to the nearby Pasir Gudang Health Clinic for treatment.

Tan said that he was informed that the victims suffered from symptoms of vomiting, shortness of breath and dizziness.

"None of the affected pupils have been hospitalised and they have been allowed to return home after receiving treatment from the health clinic,” he said, noting that 17 of the 33 pupils were recorded as recurring cases in the previous air pollution incident.

Tan, who is also the Jementah assemblyman, said the Johor government took a serious view of the latest incident in SK Taman Pasir Putih today.

"The Pasir Gudang Municipal Council has been instructed to take immediate action as soon as possible.

"In addition to that, integrated air quality monitoring measures will be carried out by various government agencies from time to time,” said Tan.

SK Taman Pasir Putih has a total of 1,119 pupils with two school sessions.

In June, 15 pupils from the nearby Sekolah Agama Taman Mawar and SK Pasir Gudang 4 were treated after suffering breathing difficulties and vomiting.

This follows a second bout of air pollution in Pasir Gudang following the major pollution incident in March where more than 4,000 people, mainly children, fell ill after the toxic fume incident in Sungai Kim Kim.

The fallout from the incident also saw the temporary closure of 111 schools in the Pasir Gudang district.