Emergency services were called to what was initially reported as a ‘‘hazardous substance’’ incident on Friday morning at Church of the Holy Name on Sealy St, Ashburton.
However, investigations since, considered substances including hydrogen cyanide, carbon dioxide and carbon monoxide, have returned non-concerning results.
Four children in a minor condition were transported to Ashburton Hospital by ambulance.
Father Joselito said he was leading weekly mass for St Joseph’s School children when, towards the end of Eucharistic prayer about 9.30am, the incident happened.
He understood what had occurred was one child fainted, then others felt ill.
At the time the mass continued while teachers attended to the children. Afterwards he saw emergency services had been called.
‘‘I was surprised when ambulance, police and fire brigade there, I was wondering what’s happening.’’
Incense was not used during the service. Investigation of the church’s heating system, which had been operating for about half an hour before the service, showed zero levels of carbon dioxide and carbon monoxide in its air stream.
‘‘Rest assured that we care for the health and safety of everybody in the church,’’ Father Joselito said.
Ashburton Volunteer Fire Brigade responded alongside crews from Timaru and Washdyke.
A Fire and Emergency New Zealand spokesperson said firefighters detected ‘‘extremely low amounts’’ of hydrogen cyanide.
‘‘But it was such a low amount that it barely registered. There was no further investigation.’’
Hydrogen cyanide can cause headaches, vertigo, apprehensiveness and shortness of breath at low concentrations, according to the World Health organisation.
The chemical can be used as a fumigant by professional operators to exterminate rodents and wood-boring insects.
On Wednesday, St Joseph’s School principal Cath Blacklow issued a statement that said “last Friday, a number of pupils fell ill at St Joseph’s School and at our neighbouring church.
“Emergency personnel discovered very low levels of a chemical. Emergency personnel did not consider any additional investigations were necessary and thankfully, the pupils recovered quickly.
“As a precautionary measure, and given our high priority for student safety, the school asked that more testing be undertaken, including by professional fire crew and tradespeople, she said.
“It was established that no chemicals were detected at the church or areas tested within the school that would be connected with the student illnesses on Friday.”
