March 4, 2026
Fire and Emergency NZ (FENZ) has revealed the toxic chemical detected at St Joseph’s school, which led to four people being taken to hospital.
A FENZ spokesperson confirmed its crews “detected extremely low amounts of hydrogen cyanide at the church” on Friday [Feb 27].
“It was such a low amount that it barely registered. There was no further investigation.”
The spokesperson did not clarify the source of the chemical.
FENZ previously stated it had sent three crews to the school just before 10am Friday, and called for its hazmat unit from Timaru.
Firefighters left soon after and the hazmat unit was stood down before arriving.
At the time, FENZ said testing showed low readings of an unknown chemical, which has now been revealed to be hydrogen cyanide.
Hydrogen cyanide (HCN) is a highly toxic, colourless (or pale blue), and volatile liquid or gas with a distinct bitter almond odour.
Exposure can lead to immediate symptoms such as dizziness, headache, nausea, and rapid breathing.
It can potentially block oxygen utilisation and cause death, especially in confined spaces.
St John reported that two ambulances and one operations manager attended the scene where four patients, all in minor condition, were transported to Ashburton Hospital.
St Joseph's principal Cath Blacklow declined to comment on the incident or provide an update on the four people who were hospitalised.
Blacklow had been asked about what chemical had been detected, if the exposure source had been identified and contained, and if there would be an investigation into the incident, as well as an update on the four hospitalised people.
A member of the school board also declined to comment on the incident.
The Ministry of Education confirmed it is in contact with St Joseph’s and have offered support if needed.
“FENZ attended the incident on Friday and are the lead agency for assessing and responding to the chemical detection,” a spokesperson said.
Questions about the substance involved, its source, or any investigation were referred to FENZ.
By Jonathan Leask
Fire and Emergency NZ (FENZ) has revealed the toxic chemical detected at St Joseph’s school, which led to four people being taken to hospital.
A FENZ spokesperson confirmed its crews “detected extremely low amounts of hydrogen cyanide at the church” on Friday [Feb 27].
“It was such a low amount that it barely registered. There was no further investigation.”
The spokesperson did not clarify the source of the chemical.
FENZ previously stated it had sent three crews to the school just before 10am Friday, and called for its hazmat unit from Timaru.
Firefighters left soon after and the hazmat unit was stood down before arriving.
At the time, FENZ said testing showed low readings of an unknown chemical, which has now been revealed to be hydrogen cyanide.
Hydrogen cyanide (HCN) is a highly toxic, colourless (or pale blue), and volatile liquid or gas with a distinct bitter almond odour.
Exposure can lead to immediate symptoms such as dizziness, headache, nausea, and rapid breathing.
It can potentially block oxygen utilisation and cause death, especially in confined spaces.
St John reported that two ambulances and one operations manager attended the scene where four patients, all in minor condition, were transported to Ashburton Hospital.
St Joseph's principal Cath Blacklow declined to comment on the incident or provide an update on the four people who were hospitalised.
Blacklow had been asked about what chemical had been detected, if the exposure source had been identified and contained, and if there would be an investigation into the incident, as well as an update on the four hospitalised people.
A member of the school board also declined to comment on the incident.
The Ministry of Education confirmed it is in contact with St Joseph’s and have offered support if needed.
“FENZ attended the incident on Friday and are the lead agency for assessing and responding to the chemical detection,” a spokesperson said.
Questions about the substance involved, its source, or any investigation were referred to FENZ.
By Jonathan Leask
