Four firefighters were hurt while putting up a ladder at the scene of a blaze on Pittsburgh's South Side Slopes on Thursday. 

Fire officials say the first responders were injured when the ladder slid and made contact with a live power line close to the burning home on Monastery Avenue. Four firefighters were taken to the hospital for observation after they were shocked. 

According to the incident commander, when they rolled up on Thursday morning, they found a significant fire on the third floor. As the injured firefighters were tended to, the rest of the first responders continued to battle the flames. 

"Everybody is familiar with this area, so they're familiar with the tight and closeness of quarters of houses upon each other and overhead obstructions with wires and telephone poles and other things that exist, so we're fully planned and prepared for this at all times," said Assistant Fire Chief Matthew Davis. 

"It's not easy," said KDKA-TV's Ross Guidotti.  

"No, it adds a whole other element," Davis responded. 

Based on belongings found on the third floor, fire officials believe it was occupied, but no one was inside at the time. 

The four firefighters taken to the hospital are in stable condition. The fire chief expects they'll be OK. 

The cause of the fire is under investigation.