MACEDONIA, Ohio — Three people are hurt after an explosion at the Royal Chemical plant in Macedonia on Wednesday. 

Authorities said one person is in critical condition. 

The Macedonia Fire Department said the explosion caused a sodium hydroxide spill, which shut down South Freeway Drive in both direction and forced the evacuation of the facility. First responders said sodium hydroxide isn't flammable, but it's corrosive and can burn the skin. 

The blast was so powerful, a tanker was torn in half, and half of it ended up inside the building, first responders said. 

The spill has since been contained, and it's not clear what caused the explosion.

“They've been in our city for 30 or 40 years, and we've been here before and incidents, and they have a good safety record," said Brian Ripley, fire chief of the Macedonia Fire Department. "So the investigation will tell us what happened, and they'll make changes if necessary.”

Ripley added there is nothing in the air, and anyone who lives in or passes through the area is safe.