An Edmonton homeless man taking shelter in a dumpster has died after he sustained serious head injuries when the dumpster was emptied into a recycling truck.

Police and EMS crews were alerted at 10 a.m. on Saturday after a city worker discovered the man.

Authorities are now investigating whether the man, believed to have been in his thirties, was put in the dumpster by someone else or if he was taking shelter.

"We're really not sure. The investigation is on going, but dumpsters have been known to be occupied by people to get them out of the elements," Staff Sgt. Doug Fedechko of the Edmonton Police Service told CTV Edmonton.

The driver is said to have followed procedure by checking the bin first before hooking the dumpster onto his truck, but in the process of unloading the bin, he noticed the man.

The driver of the Edmonton city recycling truck, a veteran worker, was visibly shaken by the incident.

"What I would like to say to anyone who is contemplating going into one of these bins, is to consider it like a refrigerator. Consider it an area where you are not allowed to go in because there is a danger there," said Roy Neehall, a spokesperson from the city's waste management office.

Residents in the area were surprised and saddened by the news of the man's death.

"I've never heard of that happening before and I don't expect I'll hear of that sort of thing happening again soon. Although, it causes a little bit of concern," local resident Terry Harris said.

Citizens may be startled to know that people sustaining serious injury from sleeping in dumpsters is a growing problem.

Last May, two Edmonton men narrowly escaped serious injury after garbage trucks dumped the bins they were in.

Outreach workers speculate increased security in buildings is making dumpsters a more attractive option for surviving the cold.

Controversy was sparked this week when the City of Vancouver announced the city's engineering-services department is conducting studies that will serve as a basis for a new bylaw requiring the locking of dumpsters of at least one cubic yard in volume.

The city's proposed by law is in response to complaints by waste management crews that minimum standards for dumpster cleanliness are becoming harder to maintain due to public littering.

Advocates for dumpster divers in Vancouver maintain the city is more concerned with gentrification than people who make their living from rubbish in the bins.

With a report from CTV Edmonton's Carla Shynkaruk