PORTLAND, Ore. -- Three firefighters, three civilians and two police officers were injured in two simultaneous natural gas explosions that completely destroyed a building at Northwest 23rd Avenue and Glisan Street in Portland Wednesday morning.

Portland Fire & Rescue reported that there were no fatalities from the explosions.

Portland Fire & Rescue Lt. Rich Chatman said none of the injuries to the firefighters were life-threatening. The most significant injury to a firefighter was a broken leg that required surgery. Another firefighter suffered a broken leg, but did not need surgery, Chatman said. The other firefighter's injuries were less severe.

The police officers' injuries were not life-threatening.

The names of the people injured in the explosion have not been released.

Legacy Emanuel Medical Center treated four of the injured people, including two firefighters, one police officer and one civilian. One of the firefighters was still being treated as of Wednesday afternoon. The other three patients were treated and released.

A third-party contractor hit a gas line at a mixed-use building at about 8:55 a.m. Wednesday and reported it to building occupants, who reported it to Northwest Natural Gas.

"We know there was a lot of gas in there," Chatman said.

The call came into Portland Fire & Rescue at 9 a.m.

VIDEO: Scenes from explosion in NW Portland

Crews from NW Natural Gas and Portland Fire & Rescue responded to the report of the natural gas leak and decided to evacuate the building and other buildings in the area.

Portland Fire Chief Mike Myers credited Lt. Peter St. John with "single-handedly saving lives" by helping quickly evacuate the affected building. St. John was one of the firefighters injured in the explosion.

Businesses inside the building where the explosion happened include Dosha Salon and Portland Bagelworks. Both businesses reported that everyone got out before the explosion.

About 20 minutes later, while people were being escorted out of the area, a "significant explosion" happened from inside the building at about 9:39 a.m., according to Chatman.

A source told KGW that a Portland Fire & Rescue firefighter used his body to shield an injured firefighter during the explosion.

Portland Mayor Charlie Hales said firefighters did a great job getting people out of harm's way following the gas leak.

"It's a scene like none other that I've ever seen. Fortunately we believe no one was killed in this incident," Hales said. "Huge credit to the Portland Fire Bureau for getting on scene, sizing it up and getting people out of the way."

Hales said people can contact the Mayor's Office to donate money or goods to those affected by the explosion.

"There's a lot of impact on people's lives and we're going to need the community to come together to help those folks," he said.

The American Red Cross opened a reception center for people affected by the explosion. It is located at Beth Israel at 1972 NW Flanders Street.

PHOTOS: Explosion in NW Portland

At its peak, about 100 firefighters were at the scene, putting out hot spots from outside the building. Structural engineers, after an inspection, said the building was not in danger of collapsing.

A spokesman from NW Natural Gas said customers in the area can expect gas outages, but once the area is secure and safe, gas will be turned back on.

About 420 students at Metropolitan Learning Center at 2033 NW Glisan Street were evacuated as a precaution Wednesday morning, though police said the children were not in danger.

The students are safe and healthy at Portland School District headquarters at 501 North Dixon. Parents have been instructed that they can pick up their children at any time Wednesday. Parents should park at the Moda Center, across from the district headquarters, when they pick up their children.

Earlier reports said that children at Chapman Elementary reported feeling sick from the smoke, but the principal at Chapman said the children are doing well and still in school.

The public is being cautioned to avoid the area. Traffic delays within a three-block radius of the explosion should be expected.

The Bureau of Alcohol, Tobacco, Firearms and Explosives is investigating the explosion.