TULSA, Oklahoma - People near 41st and Sheridan are now going back in their homes after being evacuated Tuesday afternoon for a chemical spill.

The Tulsa Fire Department gave the all clear for residents to return home after working on the leak for more than five hours.

Firefighters say the leak happened at Windsor Food.

Tulsa police were some of the first to notice the strong smell when they responded to a five-vehicle crash in the area.

Police and firefighters say they suddenly smelled ammonia and it was so powerful that it “knocked them off their feet.”

“Our fire crew was working that accident and the smell, it will take your breath away,” said Tulsa Fire Department’s Captain Justin Lemery.  “It’s definitely a strong smell.”

Tulsa Fire Department’s hazmat crew responded to help locate the source of the smell.

“Located where that ammonia smell was coming from.  It was an actual leak,” said Lemery.

Firefighters evacuated employees from Windsor Foods and ordered evacuations of a three-block area near the leak, from 41st to 44th along South 70th East Avenue.

Some buildings in the area were evacuated, and others right next to the business were told to shelter in place.

People who sheltered in place were told to turn off their air conditioners so the chemical would not be sucked into their homes and offices.

“We were always ready to evacuate more people if we needed to,” said Lemery.  “We had other fire crews in that area that, if we thought it was necessary, we could have gotten them out of there.”

He says it was a refrigerant coolant leak they believe is isolated to one room of the business, but the cause of the leak is still undetermined.

There was an ammonia leak at the same business several years ago.  That time, it was a forklift that cut a line to an ammonia tank.