Fire crews were still on scene at the old CharlesTown USA Mall Saturday to put out hotspots from Thursday’s massive blaze.

"We decided that we were going to come down and hit whatever hotspots that are in the building and try to eliminate the areas that are still smoldering,” Frankfort Center Assistant Fire Chief Fred DiStefano said.

The hotspots were caused by smoldering buried debris. After the Utica Fire Department worked to put out some of these areas Friday night, crews returned Saturday and worked throughout the afternoon.

"Our main goal is to make sure that whatever hotspots we have, we want to make sure they're out and once we leave hopefully we won't have to come back,” said DiStefano.

Firefighters were dispatched to the abandoned mall just before 1:30 Thursday morning, when the complex was engulfed in flames.

Since getting the fire under control, first responders say many neighbors have been in the area for photos and videos.

They’re warning these individuals to stay clear of the building.

"The integrity of this whole complex is gone,” said DiStefano. “Somebody can get in there, this building can come down on them, and unfortunately they're going to lose their life. So we want to make sure everyone knows that, listen, stay away from it."

One of the big concerns from the fire was air quality throughout the Mohawk Valley. Frankfort Center’s Assistant Chief says State Fire set up air quality monitors throughout the area.

"They deemed that there's no issues anymore,” he said. “Most of the areas that you have right now, like I said earlier, are just steam pockets, there might be a couple of smoldering things but at this point, I don't know of any air quality issues."

The cause of the fire is still under investigation.