Horne Smelter has been operating a sulfuric acid plant since 1989. This proven technology is widespread in the metallurgical industry. The plant treats process gases to convert them into sulfuric acid. Sulfur dioxide (SO2) is collected, cleaned, and converted to sulfur trioxide (SO3) before being turned into sulfuric acid.

This infrastructure is designed to reduce the environmental impact of the smelter’s operations. In fact, the Horne Smelter sulfuric acid plant is among the world’s most efficient, with a sulfur capture rate of over 96%—well above the 90% standard.

The sulfuric acid produced by Horne Smelter plant is of very high quality. It is resold on the market and used in the food, pharmaceutical, and fertilizer industries, among others.

Risk of SO2-SO3 leakage

Although highly unlikely, there is a risk of SO2 and SO3 gas leakage with the potential to impact the surrounding population. However, a leak can be immediately stopped by turning off the fan and shutting down the smelter. No such leaks or emergencies have ever occurred. In addition, a wide range of controls are in place to prevent any leakage:

  • Inspection and maintenance program
  • 14-unit leak detection system
  • Automatic plant shutdown system
  • Warning siren
  • AGIR instructions
  • Training for sulfuric acid plant employees 
  • Emergency measures

In 2000, a joint initiative was introduced by Horne Smelter, the city of Rouyn-Noranda, public health authorities, and Direction de Sécurité civile. Impact modelling was conducted, which led to the development of a management plan with the various stakeholders, including the AGIR instructions. A warning system (siren) was also implemented, in addition to a public communications strategy.

What is the AGIR campaign?

Since the first risk assessment was conducted in 2000, the population of the Notre-Dame neighbourhood has had time to change. In addition, modelling technology and applicable standards have evolved over time.

Since the modelling led to an adjustment of the security perimeter and the last information campaign on the risk of an SO2 and SO3 leak was conducted several years ago, a decision was made to roll out the campaign S'informer pour mieux AGIR (Find out more to better take action). In doing so, the smelter ensures that all residents inside the security perimeter know what to do in the event of an incident.

The warning siren

If an SO2 or SO3 leak occurs, a warning siren will sound. The siren sounds like the horn of a cargo ship. 

Note that siren tests are conducted every first Wednesday in March, June, September, and December. To avoid confusion, these tests are announced beforehand through:

  • Local radio stations
  • Horne Smelter’s Facebook page 

AGIR instructions

If you hear the siren of the sulfuric acid plant and are within the security perimeter, you must take the following actions (AGIR approach):

Translation: Take shelter, Keep doors and windows closed, Turn off ventiliation and air conditioning, Watch TV, listen to the radio.

SAM, the automated message system for your safety and your family’s safety

The city of Rouyn-Noranda has implemented an automated message system (SAM) to reach citizens during an emergency, such as an SO2 or SO3 leak.

When necessary, a recorded phone message is sent to residents on the municipality’s call list. If you’re away, the system will leave a message on your voicemail.

Sign up or validate your information

Your contact information will automatically appear on the automated call list if your home, business, or industrial telephone number (landline) is listed in the white pages of a telephone directory. However, it’s best to validate your contact information by visiting the city of Rouyn-Noranda website.

If you have only a cell phone or if your phone number is unlisted, you must sign up for the automated message system. This involves creating an account with your cell phone number, adding the required personal information to your file, and updating the information whenever necessary.

You can sign up free of charge via the city’s website or directly at city hall. www.rouyn-noranda.ca/sam.

Frequently Asked Questions

A siren has been in place since 2000 to warn people in the event of a leak, even though a leak is unlikely. The siren is tested every three months and radio ads are broadcast to let people know about the test and remind them of the AGIR instructions. A message is also posted on the Horne Smelter Facebook page.

The sulfuric acid plant is inspected and maintained daily. Also, the sulfuric acid plant is equipped with a leak detection system that is periodically upgraded. If concentrations above a certain level are detected, operations are automatically shut down.

Horne Smelter also has a contingency plan, which is updated annually. It is shared with various partners, like the fire department and the Sûreté du Québec, for example.

Finally, a warning siren may sound if there is a leak. The siren can be heard throughout the security perimeter and even beyond. If it sounds, the AGIR instructions are deployed and communicated by radio, television, and the automated message system (SAM).

The risk associated with SO2 and SO3 concerns all citizens, institutions, businesses, and organizations located within the security perimeter.

Potential symptoms vary depending on the concentration of leaked SO2 or SO3. According to public health authorities, the following symptoms may be observed for concentrations of:

0 - 3 ppm 3 - 15 ppm > 15 ppm
Odour Nose and thorat irritation Respiratory irritation: rhinitis, laryngitis, bronchitis
Mild nose, eye, and throat irritation Cough, sneezing Bronchial constriction
  Conjuctivitis Potential for pulmonary edema
  Difficulty breathing Conjunctivitis with tearing
    Headache, nausea, and vomiting

The city of Rouyn-Noranda’s municipal emergency preparedness plan is aligned with Horne Smelter’s emergency response plan. This plan includes a procedure to quickly assemble the teams responsible for assisting the population and carrying out emergency measures where necessary.

The city of Rouyn-Noranda’s Sûreté du Québec detachment, its fire department and emergency services department, ambulance services, and the municipal employees concerned are always ready to deal with an emergency, provide essential services, and inform the public of the required actions.

As soon as they hear the warning siren, citizens must apply the AGIR instructions:

  • Take shelter immediately inside your home or another building
  • Keep all doors and windows closed
  • Turn off all ventilation and air conditioning systems
  • Watch TV or listen to the radio for more information

If there is a leak, citizens outside the security perimeter are not required to apply the AGIR instructions.

However, they may still feel symptoms. Even at lower concentrations, sensitive individuals outside the perimeter may smell a persistent odour of SO2 and may experience nose, eye, and throat irritation. Anyone who feels unwell should stay indoors and apply the AGIR instructions.

Although located on the edge of the perimeter, the school is encouraged to apply the AGIR instructions. We ask parents not to pick up their children, as the students will be inside and all doors and windows will be closed. Parents will be notified by the school once the lockdown notice is lifted.

The public will be notified that the notice is lifted through television and radio messages. Posts will also be made to the Horne Smelter Facebook page.

No. Smells in the neighbourhood are often associated with poor weather conditions, most often northerly winds blowing into the city.

There are two main reasons for this.

  1. Most sulfur dioxide odours that are noticeable in the neighbourhood are due to “fugitive emissions.” In the smelting process, sometimes, depending on vessel operation, certain gases are not fully captured by the main ventilation and are then sucked outside through the roof vents. These fugitive sulfur emissions can be smelled or perceived in the nearby neighbourhood.
  2. Another weather phenomenon can cause what’s called a downwash. When this happens, the gases coming out of the main stacks are downwashed or pushed to the ground instead of rising in altitude. This is when sulfur can also be smelled.