A single male occupant inside a van that struck a building in southwest Calgary has died on scene.

Emergency crews were called to the building, located at 17 Ave. and 11 St. S.W. shortly before 5:30 a.m.

Police say that the van was driving south on 11 St. approaching 17 Ave. when it drove through the intersection and mounted the south-side crosswalk.

The vehicle then struck the building at the corner of 1137 17 Ave. S.W.

According to witness reports, the van didn't appear to slow down as it proceeded through the intersection and then slammed through a metal fence and into a building.

Upon impact, the propane gas tank ruptured and began to leak.

Crews managed to shut off the fuel tank to prevent any leaks from the damaged engine so they could attend to the driver.

Once that was dealt with, crews found the 64-year-old male driver unconscious and trapped inside the van.

The van had sustained sigificant front-end damage and crews say that it made the extrication difficult. "The front end had to be pushed away from the rest of the vehicle to extricate the patient," says Acting District Chief John Cherweniuk.

After the patient was free from the wreckage, he was turned over to Calgary EMS, who declared the man dead on scene.

Adam Loria of Calgary EMS says that it is difficult to detemine the exact cause of death, but when paramedics assessed the patient, they found they couldn't do anything to help. "He was declared deceased on scene due to the injuries sustained."

Investigators are awaiting the coroner to determine his exact cause of death and find out if there was any medical emergency prior to the crash.

Loria also says that two police officers had to be transported to hospital for precautionary measures.

The pair were the first responders to the crash and paramedics made the determination that they may have inhaled a bit of propane leaking from the wrecked van.

Emergency crews had to close down a section of 17 Ave. and 11 St. S.W. to aid with the crash investigation.

It reopened at about 9:30 a.m. on Thursday.

Cherweniuk says that the CFD's heavy rescue unit has inspected the building and found it to be structurally sound.

The investigation continues.