JOHOR BARU (THE STAR/ASIA NEWS NETWORK) - Thirty people, including 18 students, have been admitted to hospital after being exposed to hazardous gas from chemical waste that was illegally dumped into a river in Johor Baru.

Senior state health official Sahruddin Jamal said on Thursday (March 7) that 21 patients had been taken to Sultan Ismail Hospital, six to Pasir Gudang Health Clinic and another three to Penawar Hospital.

"Two victims, including a student, had to be intubated, as their respiratory systems were blocked," Dr Sahruddin said at a press conference.

"The rest of the victims are in stable condition," he added.

He said the authorities had taken samples from the river, Sungai Kim Kim in Pasir Gudang.

Dr Sahruddin said the chemical had apparently been dumped where a bridge is being constructed.

State education official Aminolhuda Hassan said at the press conference that the students were from SK Taman Pasir Putih and SMK Pasir Putih.

"Following the incident, the Johor Education Department has taken the decision to shut down the two schools until further notice," Mr Aminolhuda said.