PORTLAND, Ore. (KOIN) – Officials said the cause of a deadly retirement home fire in St. Helens Wednesday morning was an accidental human-caused fire, Columbia River Fire & Rescue announced.

Shortly after 12:30 a.m. crews responded to the 3-alarm fire at the Columbia Hills Retirement Center on Pittsburg Road. An explosion caused the fire to spread across the complex, according to fire personnel.

On Friday, the fire department said the explosion was caused by oxygen cylinders that were stored in the apartment where the fire started.

Three officers were the first to arrive at the scene and body camera footage from St. Helens Police Department showed how they quickly began to help residents out of the building.

A firefighter reportedly found one person unconscious in the hallway of the building where the fire began and carried her outside. Officials said they provided CPR and resuscitation efforts however she was pronounced dead on the scene.

Five other residents were rushed to local hospitals for treatment. A firefighter and a police officer were injured in the blaze, as well.

While six units out of 31 in the complex were heavily damaged, and others were damaged by smoke, the Red Cross helped many residents move to local hotels while others left with their families, officials said.

The fire department said the retirement home had working smoke detectors and noted it was “more than capable of alerting tenants.” However, officials pointed out the facility did not have a sprinkler system – noting it was not a code requirement when it was built.

Donations to the Red Cross can be made through their website, where donors can specify if they want to assist the tenants of Columbia Hills Retirement Center, Columbia River Fire & Rescue said.

The fire department added that Scouts are hosting a drive at the St. Helens Ace Hardware on Saturday, Oct. 8 from 8 a.m. to 4 p.m. collecting donations along with cash and checks.

Fire officials stress the increased fire danger oxygen cylinders can have in homes and provided safety tips.