Emergency services were in a race against the clock to save a man who was trapped inside a garbage truck under a pile of waste in on Wednesday morning.

A passerby heard screams coming from inside a Recology truck in San Francisco just after 4am and alerted the driver who immediately stopped the vehicle and turned off the engine.

Dozens of firefighters raced to the scene and quickly realised the complexity of the rescue mission as they could not simply unload the truck without putting the man trapped inside at greater risk, San Francisco Fire Department’s public information officer Mariano Elias told People.

Instead, the group of 25 firies began removing the rubbish by hand, working for more than two hours by digging through the compacted waste to reach the man.

The man remained conscious and continued to yell out to rescuers as they worked to find him.

Once crews manged to pull the man to safety at about 7am, paramedics administered an intravenous drip in an effort to prevent him from suffering crush syndrome.

According to Australia Wide First Aid, crush syndrome is a severe condition that occurs when a crush injury causes a person’s muscles to become damaged, releasing toxins into the bloodstream.

Urgent medical treatment is required to treat the life-threatening condition or the victim could suffer organ dysfunction, local tissue injury or metabolic abnormalities.

The man was rushed to Zuckerberg San Francisco General Hospital in a serious condition.

Elias said the man became trapped inside the truck after the vehicle picked up a rubbish bin he was in and dumped him into the back and surviving the compaction mechanism.

“I personally heard him yell a few times. I don’t know if that was in pain or just frustration.” Elias said.

“It’s an unfortunate situation to lead someone to go into a dumpster, whether that was to sleep or fish through some things to find something for himself or something to eat, but the good part of his outcome is that he’s alive,”

Recology is continuing to investigate the incident, which has been labelled as “unusual” by company spokesperson Robert Reed,