One teacher was flown to Lenmed Ethekwini Hospital and Heart Centre while more than 100 pupils were taken to Prince Mshiyeni Memorial Hospital.
By midday critical patients were on an oxygen supply in the medical emergency ward.
Parents were standing in the corridors and told the Daily News they had no idea what happened.
Garrith Jamieson, Rescue Care director, said a chemical substance had been emitted through the school.
“It’s alleged some pupils were playing with a ball which tore open and a powder substance was spilt. This was then picked up by the wind and entered classrooms, affecting multiple pupils and teachers,” Jamieson said.
“Four patients, a teacher and three pupils sustained critical injuries.”
He said the patients were coughing, collapsing and complained about itchy throats. He also said the SAPS bomb squad was called in and took over the scene.
A grandmother said she was distraught.
“I was told to rush to the scene. I thought my grandson was dead,” she said.
She said pupils wanted to hit her grandson because he allegedly found the ball and brought it to school.
“I am upset. When I look at him, he doesn’t look okay,” she said.
One teacher, who did not want to be named, said the powder caused the pupils and teachers to fall ill instantly, while others fell ill after some time.
“They coughed, others fainted and some were rushed to the clinic. By the time they got to the clinic they were having seizures,” he said.
The teacher said others struggled to see.
“The substance was rolled in toilet paper and given to the police,” he said.
Durban metro police spokesperson Glen Ndlovu said the SAPS bomb squad would investigate the ball’s contents.
Department of Education spokesperson Kwazi Mthethwa said they were monitoring the situation.