A Fire and Emergency service spokesman says he does not believe the mystery substance affecting dozens of children at a Wairarapa school came from a plane.
It had been widely thought that a chemical came from a plane flying over South End School in Carterton.
But Fire and Emergency incident controller Brett Lockyer told Newstalk ZB that he didn't think that was the case.
"We've had some reports about that," Lockyer told Larry Williams.
"But that's been unsubstantiated at this stage and we don't believe it's come from a plane ... we just don't know where it's come from. That's a mystery to us at the moment."