An ammonia leak at a cold-storage plant forced the evacuation of at least 300 residents and closed roads for about 90 minutes, authorities say.

The leak was reported about 6 p.m. Monday and came from a Price Cold Storage and Packing Co. Inc. building in this town northwest of Yakima, fire officials said.

No injuries were reported, although residents complained of the strong smell.

High outside temperatures apparently caused ammonia gas in a valve system to expand, activating a pressure-release mechanism that allowed invisible ammonia vapors to seep into the air, fire Capt. Miles Kohl said.

The high temperature in Yakima was 92.

The amount of ammonia released was not known. The leak continued for about 30 minutes before the system was cooled down by water from a hose, Kohl said. The leak was eventually contained and the system shut down.

No one was working inside the building when the leak occurred, he said.

Residents who live immediately downwind of the plant were told to leave, and area roads were cordoned off.