Ten-year-old James was playing outside his Wairarapa primary school when he smelt something bad and got called inside to his classroom.
He was one of dozens of children affected by an unknown chemical found near the South End school playground in Carterton.
"I smelt it, it smelt like poo and manure and rotten stuff and smelt really bad and then I ran to my classroom," he told Newshub.
"We had to stay there and then we went to the ambulance and I had to have the shower."
15 people were taken to hospital in a moderate condition, while 40 were treated at the scene with "very minor" symptoms according to Wellington Free Ambulance. All of the patients have since been discharged.
Over 100 people went through a decontamination process with the Fire and Emergency Hazmat (hazardous materials) unit at the scene.
James' brother Ben was one of the more seriously affected children and was hopsitalised.
"I think he is feeling really sick, some other people vomited but he didn't, we were lucky and so was he."
Parents of students at the school were advised to go home and get clean clothes for their children on Friday afternoon because they would need to go through a decontamination process.
James's father Ben says the ordeal has been a stressful one.
"I came home from work and had to come up here, but I think the community responded positively, all the parents were standing outside supporting one another... A bit of unknown there, we didn't really know what was going on or what had happened"
South End School said in a post on Facebook that there was a "very strong smell" in the playground.
"A plane flew in a southward direction and one student had seen 'stuff' coming out of the plane - so we assume it was a fertiliser of some sort," the post said.
The nature of the substance remains unclear, and police are investigating.
Newshub.
