If you live near the following nine factories, you may hear an alarm go off for about three minutes Tuesday afternoon.

That's because factories that use dangerous materials will be testing their emergency alert systems around 2 p.m.

They are:

Molson Coors on Notre-Dame Street East in Ville-Marie.

Labatt Breweries on Labatt Street in LaSalle.

Centre de distribution Pêcherie Atlantiqu​e on François-Bricault Street in Rivière-des-Prairies–Pointe-aux-Trembles.

Centre de distribution Viandes et surgelés Montréal on Albert-Hudon Boulevard in Montreal North.

​Entreprise Indorama PTA on Sherbrooke Street in Montreal East.

Suncor's sulphur factory on Cherrier Street in Montreal East.

The Saputo factories in Saint-Laurent and Saint-Léonard.

The Parmalat plant on St-Jacques Street in Nôtre-Dame-de-Grâce.

The tests are carried out in order to make sure the equipment works and emergency services are prepared in case of an actual emergency.

The sirens serve to warn people who are outside to take shelter in the event of a major industrial accident. Those who want to be warned of the real thing via text message can sign up for alerts here.

What to do in a real emergency:

The city is also reminding people that if an accident really were to occur, citizens should: