He said one patient was involved, and no fires were reported.
Hato Hone St John said they were notified of the workplace incident and responded with one ambulance and one rapid response unit.
One patient, in serious condition, was taken to Middlemore Hospital.
A worker at a neighbouring property told the Herald his customer saw a fire truck and an ambulance at Southpac Trucks.
About 10 minutes later, he could see emergency services on the scene, but could not see what was happening.
WorkSafe is aware and is making initial inquiries into the circumstances.
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