CHARLES CITY, Iowa — Authorities say firefighters from at least eight departments responded to a blaze that heavily damaged a building at an egg facility on the west side of Charles City in northern Iowa.

Firetrucks were dispatched a little before 5 p.m. Monday, and their crews remained at the Zoetis (zoh-EH’-tis) facility until nearly 11 p.m. Charles City firefighters returned around 12:30 a.m. Tuesday to handle a flare-up and some hot spots.

One firefighter suffered a minor leg injury. Zoetis spokesman Bill Price said Tuesday from the company headquarters in Parsippany, New Jersey, that no employees of the animal health company were injured.

He says several thousand chickens that produced eggs for vaccine manufacture were killed.

Charles City Fire Chief Eric Whipple says an arcing electrical wire started the fire.