Interstate 90 was shut down for about an hour Wednesday evening between U.S. Highway 195 and Exit 276 (Thorpe Road) as fire crews responded to an ammonia leak at the same business that also reported a leak Saturday.

Fire crews evacuated residences and businesses in the area around Johanna Beverage Co. at 5625 W. Thorpe Road. The leak was thought to have involved between 600 and 800 pounds of the caustic gas.

Brian Schaeffer, Spokane Fire Department assistant chief, said a leak of that size is quite large. Ammonia in a compressed gas form has a high expansion ratio when released, he said.

“A small amount of liquid released and boiling creates a large amount of vapor,” he said.

The plume was moving northeast. Officials used Alert Spokane to advise residents as far north as Sunset Boulevard to shelter in place, said Mitch Metzger, Spokane County Fire District 10 deputy chief. The affected area was bordered by Highway 195 to the east and Geiger Boulevard to the west.

“The wind isn’t as favorable (as Saturday) so we have a bigger area,” he said.

Beverage company workers had made repairs to the refrigeration system and were recharging it Wednesday evening when the leak developed just before 7:30 p.m.

“They were refilling the system when some of the seals failed,” Metzger said.

A few people reported minor symptoms such as watery eyes but no one required treatment, Metzger said.

Eight beverage company employees were sickened in Saturday’s leak and one was taken to a hospital for treatment. That leak was smaller than the amount being reported Wednesday evening.