Emergency crews have freed a 64-year-old construction worker who was trapped underneath a concrete beam at a site in the Hamilton area.

It happened just after 11 a.m. on Green Springs Road in Carlisle just northwest of Burlington. Hamilton police say the man became trapped by a fallen concrete beam and was pinned for over two hours.

"Upon arrival, we found a worker at the dam who was trapped at the base. A large slab of concrete had fallen and trapped the worker," Hamilton police told CTV Toronto.

Firefighters attempted to use airbags to lift the slab but it wasn't enough.

Crews were eventually able to free the worker sometime after 1 p.m. after a crane operator was called in to help.

Surgeons were also called to the scene to administer constant medical attention to the man.

"Because it's down at the base of the dam, we had to get under very rocky conditions. It's very humid here, so we brought in extra crews for relief. Just getting in there to stabilize the scene was a challenge," police said.

A spokesperson with ORNGE air ambulance described the man's injuries as severe. He was rushed to Hamilton General Hospital and is in serious condition.

The Ministry of Labour is investigating the incident.