Fire crews from Tokoroa and Rotorua attended with a support unit from Putāruru.
They were unsure of the concentration of hydrochloric acid but were treating it as highly concentrated and taking “appropriate precautions”, Pennefather said.
They were also getting additional advice from the Queensland Fire and Rescue scientific branch in Australia.
Just after 6am firefighters were still monitoring the site and planning for the recovery of the truck “sometime this morning”.