Emergency services have reopened State Highway 6 in Nelson after acid from tonnes of used car batteries was spilled over the road in a crash.
Early this morning a double carriage truck ploughed into another truck which was parked on the side of the road in Tahunanui.
One resident told 1 NEWS the impact of the crash woke him up, describing the sound as "a massive boom".
The female driver of the moving truck was taken to hospital with serious injuries. No one else was involved in the crash.
The stationary truck contained around eight tonnes of used car batteries, which were strewn across the road.
Sulphuric acid made its way into drains and had to be neutralised.
Fire and Emergency Senior Station Officer Craig Davies told 1 NEWS crews have checked manholes "one kilometre along the road in both directions" and are pleased to have contained the hazardous substances.
Mr Davies says they've been working with police and Nelson City Council since early this morning to manage the busy road, which is also a trucking route.