PASIR GUDANG (THE STAR/ASIA NEWS NETWORK) - The Fire and Rescue Department has identified at least 15 types of chemicals in air samples taken from areas surrounding Sungai Kim Kim, including hydrogen cyanide.
Its Johor department director Yahaya Madis said that while most of these gases were harmless, some - such as hydrogen cyanide - could be harmful if found in high concentration or if a person was exposed to it for too long.
"So far, the highest reading of hydrogen cyanide we have seen was 4.5ppm (parts per million) on March 13 at Taman Tanjung Puteri Resort," said Datuk Yahaya.
"However, the reading returned to normal after less than two hours and did not spread to other areas," he said, adding that the air quality around Pasir Gudang had improved since Friday (March 15), and the concentration of hydrogen cyanide was at a safe level of 3ppm and below.
Chemicals, believed to contain heavy metal used to dissolve metal at a scrapyard and a chemical factory in Kulai, were discharged into the river about a week ago. This led to hundreds of people being treated for exposure to hazardous fumes.
Since then, there have been three waves of air pollution as the chemicals washed downstream towards the Strait of Johor.
Energy, Technology, Science, Climate Change and Environment Minister Yeo Bee Yin said on Sunday (March 17) the clean-up of the 1.5km polluted stretch of Sungai Kim Kim was complete.
"The 1.5km stretch of Sungai Kim Kim that was polluted has already been cleaned up but today we want to see what more 'touch-ups' can be done," Ms Yeo was quoted by Bernama news agency as telling reporters at the state Disaster Management Committee's operations room.
"Today can be said to be a day of monitoring. After that, then only we can look into what further action is needed," Ms Yeo said.
She said 30 teams of state environment and chemistry personnel were being deployed to 30 schools around the affected area on Sunday to monitor air quality, and the results will be made public on Monday.
Earlier on Sunday, Johor's top health official said seven poisoning victims remained under intensive care while 108 others had been discharged from hospitals.
Dr Sahruddin Jamal also said in a statement that contractors involved in the clean-up operation had collected 1,250 tonnes of soil, water and sludge from the river.
Meanwhile, Pasir Gudang Amanah division chairman and complaints centre supervisor, Mr Syed Othman Syed Abdullah, has filed a police report over fake viral news about the incident.
"In one of the messages being circulated on WhatsApp, the culprit claimed a 14-year-old had died due to the toxic fumes, which is not true," he said.
"Another Facebook post claimed Kota Masai was unsafe and the public was urged to evacuate the area."
He pointed out that some of the original posts had been removed but the fake news had already gone viral.
Health Minister Dzulkefly Ahmad said the toxic fumes was a one-off "acute exposure" (short term) and it was not expected to cause long-term chronic effects. He pointed out that the level of toxicity was low and would not kill those who had been exposed to it.
"I'd like to emphasise that what we are witnessing here is an acute exposure where the dose is not fatal," said Datuk Seri Dzulkefly.
Asked if villagers and residents living near the river should be evacuated during the clean-up operation, he said that it was not the ministry's jurisdiction to give such an instruction.
"The agencies did find hydrogen cyanide but it is at a very low level, which is at 5ppm," he said. "We will wait and see if there is such a need but at the moment, the clean-up operation will continue. It is already reaching almost 1km (stretch)."