PORTLAND, Ore. – A hash oil explosion was the cause of a fire that killed two people and destroyed a North Portland home Monday afternoon.

Portland Fire & Rescue on Wednesday night said the explosion occurred when a large concentration of butane came into contact with an ignition source. They said the concentration of butane was created by the homeowner while he was attempting to produce butane hash oil. The ignition source has not been determined.

The explosion killed 42-year-old Matthew McCrann and 68-year-old Richard Cisler.

McCrann's neighbor, a man who wanted to be known as “Hippie Mike,” said McCrann came stumbling into his backyard and collapsed after the explosion. The two spoke before McCrann was taken away in an ambulance.

“'I never used my dryer and I put clothes in it' and 'oh my God I hope my contractor was on break.’ Those were the last words he said to me. He was in and out and he was so much pain and there wasn't a damn thing I could do for him,” said Hippie Mike.

He described McCrann as a good guy, and a naturalist who wanted to live off the grid as much as possible.

The explosion and fire at 6214 N. Kerby Ave. sent glass and other debris flying across the street into Peninsula Park. The home where the explosion happened appeared to be a total loss.

A firefighter suffered unspecified minor injuries.

Neighboring homes on both sides of the explosion were damaged by the fire. Crews were able to save one neighboring home, but the other home was heavily damaged, if not destroyed.

Photos: Explosion, large fire reported in North Portland

Neighbors said the explosion shook the entire block.

"I was sitting up in my room watching TV and I heard this big boom explosion," said Andre, who lives on the block. "It felt like an earthquake, it felt like a water line or gas line busted."

Candace Edwards said she saw the house collapse and flames rise dozens of feet into the air.

"I just heard a 'boom.' It shook me," said Edwards.

"We all felt the shock wave and heard a super loud explosion," said Oscar Aldama-Shaw, a camp counselor working at Peninsula Park. "I saw a tree falling, thought it was a tree at first, but then we saw a whole bunch of smoke, explosion and fire and stuff."

KGW's Christine Pitawanich contributed to this story.