Emergency crews responded to reports of an ammonium leak at Belfonte Ice Cream & Dairy Foods Co., 1511 Brooklyn Avenue, after 7 a.m. on Thursday morning.
Kansas City Deputy Fire Chief James Garrett said that the leak was caused by a system failure. When the system was brought back up, the leak continued.
Four buildings in the immediate area, including a United States Postal Services office, were evacuated and traffic at Truman Road and Brooklyn Avenue was shut down to allow emergency crews and fire inspectors access to the site, according to Kansas City police.
Police also shut down East Truman Road from Prospect Avenue to the Paseo.
No injuries have been reported. Buses for those who were evacuated to take shelter in were called to the scene.
Thunderstorms had already exacerbated traffic and knocked down trees in the Kansas City-area on Thursday and the area is in a severe thunderstorm watch until 9 a.m.