A Worksafe spokeswoman confirmed the incident was being investigated.
"As the matter is under investigation, we are unable to comment further at this time."
A police media spokeswoman said police were notified by St John about a workplace accident just before 1pm.
Emergency services, including a helicopter at EastPack on Te Puke Quarry Rd. Photo / Stuart WhitakerFire and Emergency were also called to help the St Johns crew.
Eastpack chief executive Hamish Simson said the incident did not happen at Eastpack, but its site was being used by emergency services.
He said his staff had reported hearing what they believed to be an "explosion" from a neighbouring site.
Meanwhile, a person was treated for minor injuries after they got a finger stuck in an orchard sprayer in Tirohanga, near Ōpōtiki last night.
Fire and Emergency were called to the scene at 5.34pm with police and St John also attending.
One ambulance responded and staff treated one patient in a minor condition at the scene.