A tanker truck containing 3000 litres of sulphuric acid has crashed and rolled on State Highway 12 south of Dargaville.
About a third of the chemical escaped, but Northland Regional Council says it has been contained in a drain.
Another vehicle has been called from Auckland to transfer the remaining acid.
The chemical is highly toxic and response crew are wearing protective gear.
A crane will right the vehicle when all the acid is removed.
