One Corpus Christi firefighter underwent surgery Monday after he was injured in a major fire Sunday morning on Morgan Street near Baldwin. He was one of three people who were rushed to the hospital as a result of the blaze.

It was around 3 a.m. when the fire broke out. When firefighters arrived, heavy flames began coming from the first floor of the building.

One person who was staying inside the shop burned his feet and was taken to a San Antonio burn unit. Two firefighters were injured after a wall fell on to them as they were battling the blaze from outside the building.

On Monday, 3News learned that Corpus Christi Fire Department Captain Robert Harrison injured his shoulder and is at home recovering. Another firefighter, Marco Vasquez, has a broken leg and underwent surgery on Monday.

Firefighters still do not know the cause of the fire, and say it is too dangerous for them to get inside the building.

"We can't get inside because the building is unstable right now," CCFD Captain James Brown said. "The walls are still leaning and the roof is on the floor."

Fire investigators have to wait to get the proper permission from the owner to get bulldozers and go inside.