Three men who received chemical burns at an electrical site in Manawatu managed to drive themselves 30 kilometres to get help at Palmerston North Hospital.
They were injured by an unknown chemical in Kimbolton.
When they arrived at the hospital, officials evacuated the hospital's main car park and fire crews were called.
The men's ute has now been taken away for an inspection.
A Fire Service spokesperson said the chemical was still to be identified, but what was left of it had been sent away to be destroyed.
The hospital described the worker's injuries as minor and moderate, but would not reveal the nature of the injuries.
The electrical site company has launched an investigation.