Several crews from the Yonkers Fire Department and New York City's Department of Environmental Protection responded to a chemical reaction at Hillview Reservoir on Friday.

John Milgrim, a spokesman from the New York City's Department of Environmental Protection, said the reaction occurred around 11 a.m.

Milgrim said the incident happened when a contractor at the site was loading sodium hydroxide into their truck.

The caustic chemical mixed with another agent that was inside and caused the reaction.

"We had two separate engines pouring water on it to dilute it," says Chris DeSantis, who is the chief of fire prevention in Yonkers.

Officials say emergency response teams were called in out of an abundance of caution.

"Never seen anything like that before so hearing the helicopters and everything like that is different," says Yonkers resident Corey Hines.

Residents at the south end of the reservoir were briefly asked to shelter in place as a precaution.

"I heard the fire trucks, so I came down and a third one was just passing by," says Yonkers resident Elizabeth Garcia.

Milgrim said the reservoir is a huge asset to Yonkers and New York City's water, but said the supply was not impacted.

"The actual liquid that came from this reaction did flow down the driveway toward Kimball Avenue in Yonkers. [It was a] small amount there, but nothing impacted the water supply whatsoever," Milgrim said.

The spokesman said there were no injuries or wildlife harmed as a result of the response.

He said the situation was resolved.