The 60-year-old man, an employee of All Waste, the company that runs the Cromwell Transfer Station, was injured while supervising a truck disposing of waste at the site, in Barry Ave. .
He was flown to Dunedin Hospital, were he remains.
It was earlier reported he had a broken leg and possible head injury.
AllWaste Central Otago Manager Stefan Borowy said the company took the health and safety of its staff very seriously.
"We will be working hard to understand how this happened and how to avoid it in the future.
"Our thoughts are with our staff member and his family as he recovers from this incident."