The alarms, which are set to go off at 3:15 p.m. ET, were introduced last year to meet Environment Canada requirements.
The alarms will go off for three minutes at five different locations in the city, which use substances including ammonia, acetic acid and hydrogen sulfide.
Sarah Croteau, who lives less than one kilometre from one of the test sites, said she had no idea she was neighbours with a risk site.
She was surprised to receive a notice in the mail about today's drill.
“It was really alarming because we didn't know that it was dangerous to live around this area,” she says.
“I'm considering moving.”
The Labatt Brewery in LaSalle, which uses ammonia in its cooling process, is one of the sites involved in today's drill.
Nicolas Gaudreault, the engineering manager at Labatt Breweries, says there’s no need to worry.
“Since ‘52 we never had any leaks so we have an excellent record … We have crews on site 24 hours a day, seven days a week to monitor the refrigeration system,” he said.
Montreal's civil security says the drills will become a yearly event.
Officials say there is no need to take any action for today’s drill, but in the case of a real spill, residents should wait for emergency responders to come and help.
Civil security says in the case of an emergency, schoolchildren will be taken care of by staff, who are informed of proper protocol.
Anyone with questions about the drills can call Montreal civil security at 311 for more information.