Conflicting reports are emerging over what caused 10 schoolchildren to be hospitalised in Wairarapa, as authorities work to find the cause of the mysterious substance that left about 30 kids sick.

Initial reports suggested a plane dropped an unknown substance over a Carterton school on Friday afternoon.

Police confirmed there was a plane in the area but could not yet ascertain if its location was close enough to affect South End and the Montessori part of the school, where about 30 students fell ill after some reported a "sulphuric smell". Meanwhile, Greater Wellington Regional Council said it was trying to locate any flight plans that might have been filed over the Carterton area.

Piers Fuller Neve and Bronwyn Pogson, Kim McKinley and Amber Pogson heading home from South End School.

However, Fire and Emergency incident controller Brett Lockyer said claims a plane had "accidentally sprayed" the two school areas with pesticide were unsubstantiated and more "unlikely than likely". Lockyer said authorities were still unsure about what the substance was, if the reported contaminants were airborne or if a pupil may have brought something to school.

A total of 107 people had to undergo decontamination, with people near the school were also reporting illness. Some of the symptoms experienced by pupils and adults were nausea, skin irritation and redness of eyes.

The trouble started when a strong sulfur smell was detected early afternoon, forcing about 30 children to fall ill after breathing in the unknown substance. Four or five students began to vomit.

Piers Fuller After going through decontamination Oscar Rodgers said it was quite an exciting time and it tickled when the fireman scrubbed his tummy. Dad Gavin was glad that they were able to get the children out and get them home.

The 10 children taken to hospital were experiencing nausea, vomiting and slight temperatures, but were getting medical attention as a precautionary measure. All have since been sent home.

Wairarapa District Health Board spokeswoman Anna Cardno urged anyone displaying symptoms to seek medical advice.

South End School principal Claire Crawford said while everyone was "totally safe", everyone was "just trying to sort out what caused this".

PIERS FULLER/STUFF Emergency service crews at South End School in Carterton.

Carterton parent Kylie Parry's daughter Mindy, 12, was among the children who had fallen ill and was called by South End School principal Clare Crawford.

Parry, who was waiting outside the school, was told her daughter was in the care of paramedics, but was "OK".

"They've all been very professional and the principal has kept everyone really informed. Everybody is being really careful and really cautious," Parry said.

PIERS FULLER/STUFF Fire incident controller Brent Lockyer said reports of a plane dropping the substance were unsubstantiated.

Louisa Newman lives about a block away from South End School.

She said her partner Jack was playing with their two-year-old daughter, Ellie, and their neighbour's daughter, about 2pm when both girls began vomiting.

"At first we didn't know what was what happening," Louisa said. "But my father phoned and said he had read on Stuff what was happening and that's when we put it together."

PIers Fuller Indira McLellan,10, snuggles up into her jacket and towel after being decontaminated. “At first it wasn’t that bad and then people started feeling a bit sick. There was a smell. A pooey and fertiliser smell. Some people said it smelt a bit like chemicals.”

Their neighbour phoned the school and was told to take her daughter to the contamination zone.

The Newmans decided to keep their daughter at home and clean her up and wash her off. She began to perk up after about 90 minutes.

"She's resting now, and quite happy in front of Youtube."

Piers Fuller Carterton mother Jenny Gasson couldn't believe it initially when she heard the school was in lockdown. Her son Daniel was one of the children with vomiting symptoms.

Police cars and fire engines descended on the quiet rural town, but when helicopters appeared overhead, Louisa knew something serious had happened.

"It's a quiet little town so when something happens like this it's crazy."

Parry said there were "plenty of rumours going around" about the cause.

PIERS FULLER/STUFF Concerned parents gather outside South End and Montessori schools in Carterton. About 30 children fell ill after breathing in the unknown substance on Friday afternoon.

Rumours began to swirl that a delivery of mushroom compost might have been the source of the pungent, sulphur-like smell, although the mushroom farm disputes this claim and police have also ruled it out.

A person source who was in the area at the time of the incident told Stuff a delivery of Parkvale Mushrooms compost arrived at 1.30pm to an address near he school.

"It got dumped off the back of the truck about three metres from the school fence," the source said.

PIERS FULLER/STUFF Carterton parent Kylie Parry was called by the South End School principal to say her daughter Mindy, 12, had fallen ill.

"The wind changed to a southerly, blowing the odour to the school playground, so they could have smelt that."

Parkvale Mushrooms owner Clive Thompson said it wouldn't have been his mushrooms that made people to be sick.

"I don't know what it could've been, it certainly wouldn't be us," he told Stuff.

However, a police spokesman said the mushroom compost theory had been eliminated as a cause of the sickness, firstly because the delivery arrived after children began experiencing symptoms.

"Also the kids were having a strong reaction, their eyes were red and streaming so they reacted to something," police said.

Both the source and Thompson could not recall a plane flying over Carterton during the day, particularly not one that was flying low and spraying, although police said one did fly in the area. They could not find determine its location was close enough to affect the school.

PIERS FULLER/STUFF Emergency vehicles gather outside South End School in Carterton after about 30 children fell ill while breathing in an unknown substance.

WorkSafe said it would not comment on the situation at this stage, and the Ministry of Education did not return Stuff requests for comment.

Parents were asked to go home and get a change of clothes for their children, because all needed to undergo a precautionary decontamination process.



Wellington Free Ambulance executive director healthcare services Geoff Proctor said authorities were taking a "precautious approach".

"All children and their families are being looked after with extra food and water.

PIERS FULLER/STUFF Senior sergeant Mike Sutton said all parents were asked to go home and get a change of clothes for the children.

"107 people are going through a decontamination process, consisting of washing down and fresh, dry clothes," Proctor said.

Fire Emergency New Zealand spokesman Nick Venter said there were four fire crews from Wairarapa with extra support vehicles being driven over from Wellington.

The Life Flight Rescue Helicopter, with three paramedics on board, had also been sent from Wellington, but the substance had not been identified because "we're still assessing what we're dealing with", Venter said.

JOSEPH JOHNSON/STUFF New Zealand First MP and Defence Minister Ron Mark said it appeared a plane had "accidentally sprayed the schools with pesticide".

A Greater Wellington Regional Council spokesman said it had sent a team in to try and see what vehicles may have flown in the area, but they had no update on whether any flight plans had been found.