Army bomb disposal experts were called to an address in Kaipara Flats Road, close to Horse Riding Warkworth, following the discovery of suspected grenades on January 31.
Resident Deanna Yarndley found about eight of the suspicious objects while gardening in bushes on her property near the roadside. The objects were cylindrical – about the size of a slimline Coca Cola can – and had graphite rods emerging from their base.
Two members of the NZ Defence Force Ordnance Disposal Team attended the incident, along with Snr Constable Colin Murphy of Warkworth Police. Constable Murphy said the objects were badly tarnished and corroded and difficult to identify.
He said it was important to take precautions because the area had been used for exercises by American forces during World War II.
The bomb experts first thought they might be dealing with smoke grenades, which pose a danger as they generate considerable heat when activated. However, a search of an army database of suspicious objects identified them as manganese-oxide batteries. The defence force personnel removed the objects for safe disposal. Although not as hazardous as grenades, Constable Murphy said the batteries could still transfer toxic material to the hands if touched.
He said Deanna did the right thing in reporting the find because even the experts could not be sure if they were dealing with live grenades at first.
“If you find something and thinks it’s explosive, call the police,” he said.
The “grenades” turned out to be manganese-oxide batteries.