PORTLAND, Ore. -- A firefighter who's being hailed as a hero for evacuating a building before a powerful gas explosion in a popular Portland shopping district says the blast threw him up to 20 feet.

"Next thing I knew there was an explosion from the basement all the way to the third floor, each level just went off simultaneously but there was a little delay between each one," said Portland Fire & Rescue Lt. Peter St. John.

St. John said he blacked out after the blast and woke up in pain.

"And then I looked at my right leg, I knew it was broken right away and called a 'mayday,' just trying to get crews to me, I didn’t know what else to do, I was just stuck," said the 7-year PF&R veteran.

Both of his legs were broken. Fortunately, Engine 3 Firefighter-Paramedic Bret Kimple, was there to protect and treat his Lieutenant, despite being injured himself.

"Kimple was the paramedic on our engine and he was standing above me giving me medical care. And he did an excellent job giving me everything I needed," said St. John.

St. John underwent surgery into the evening Wednesday.

Fire Chief Mike Myers says St. John made several critical decisions that saved civilian lives and likely saved firefighters too. Key to that was getting people evacuated quickly.

"I feel like I’m not a hero, I just did what everybody else would have done. Because our job is to go in and protect the citizens, that’s what we’re doing to make sure everyone’s safe."

The blast injured seven people, in addition to St. John.

Two other firefighters, Kimple and Erik Kent, were hurt, along with two police officers and three civilians, but none of the injuries were life-threatening.

KGW's Tim Gordon contributed to this story.