On October 10, 1967, Chicago Fire Department Captain John S. Donovan, the acting chief for Battalion 23, suffered a fatal heart attack in the line of duty. Donovan’s battalion responded to a fire in a three-story vacant building on Komensky Avenue, and one firefighter was overcome with smoke inhalation while battling the blaze. Donovan drove the firefighter to Mount Sinai Hospital in his own departmental vehicle. As he helped the injured firefighter into the hospital, Donovan collapsed from a fatal heart attack.

He is survived by his wife.