Gas may be cause — scientist

MASTERTON: Carterton schoolchildren who were made ill from a mystery substance on Friday may have been exposed to a harmful gas, an atmospheric scientist suggests.

Atmospheric Science Global director Jennifer Barclay told The New Zealand Herald reports of the substance smelling like rotten eggs at South End school sounds suspiciously like hydrogen sulphide (H2S).

‘‘My knowledge suggests that it’s most likely a source that is close to the ground. Typical examples are sewer, rotting vegetation, anaerobic composting,’’ Ms Barclay said.

‘‘Because it smells like sul phur, the fact it smells like rotten eggs is an indicator it is a sulforaphane compound.

‘‘For the children to react the way they have it would have to be a significant source or a very nearby source.’’

Exposure to H2S can cause nausea, tearing and redness of eyes. High levels of exposure can cause dizziness, loss of appetite, fatigue and vomiting.

Emergency services descended upon the school on Friday afternoon after more than 50 children suffered headaches, vomiting and skin irritation at South End School.

Police tracked down a plane originally believed to be involved in the incident and were ‘‘90% sure’’ it did not drop anything.

Ms Barclay quashed theories of fertiliser on school grounds being a potential source, as it was dispersed in large areas.

‘‘It’s quite likely the source [was] something nearby and close to the ground [rather] than having something fly over.

‘‘If you had a source that was close to the school it wouldn’t necessarily need to be a very big source in order for the kids to be impacted by it,’’ Ms Barclay said.

The origin of the mystery substance could be tracked backwards if the weather conditions were known at the time of the incident, she added. — NZME