A man has been rescued in the US after becoming trapped in a grease vent for two days.

It happened in San Lorenzo, California.

Emergency services were called after a member of the public heard a 'faint voice calling for help' from a vacant Chinese restaurant.

Firefighters climbed to the roof using a ladder, and discovered a 29-year-old man trapped in a metal duct running between the roof and kitchen of the restaurant.

He was covered in grease and oil, and was unable to move.

Local media reports that he'd been stuck there for two days before being discovered.

Image: Alameda County Sheriff's Office via Facebook

After almost an hour, firefighters managed to remove the man from the duct.

The man was physically exhausted and dehydrated, and he was brought to a local hospital for treatment.

However, he's expected to make a full recovery following the ordeal.

In a statement, Alameda County Sheriff's Department said: "At this time, we are conducting a trespassing and vandalism investigation. It is unknown if the suspect intended to commit a burglary. The case will be submitted to the district attorney.

"We are very thankful to our citizen reporter and our firefighters for saving this man. It is likely he wound not have survived another day given the circumstances."