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Will it ever be safe to go home after Okanagan and Shuswap wildfires?

Smoke from houses destroyed by wildfires can carry deadly toxins to neighbouring homes.
Smoke from houses destroyed by wildfires can carry deadly toxins to neighbouring homes.
Image Credit: Heather Reis, Submitted.

Hundreds of homes were destroyed by the McDougall Creek wildfire in and around West Kelowna and the Bush Creek East Wildfire in the Shuswap last summer. But hundreds more homes were damaged, even if just by smoke drifting in through open windows.

That smoke, when it comes from burned houses, is full of toxins that can have long range lingering health consequences that, it seems, no one fully understands.

“Health Canada does not have data pertaining to clean up/remediation effectiveness following residential fires,” an email to from Heath Canada said. “Health Canada has not developed guidance for residences impacted by house fires, in terms of procedures for removing carcinogens and determining removal effectiveness.”

The email does include links to a number of articles and research papers on the subject, including this one called Assessing the Potential Health Risks of Wildfire Residues in the Indoor Environment.

There's lots of research on the impact of smoke on firefighters and what protection is needed for workers entering damaged sites right after a fire – whether that be a simple house fire or a wildfire.

There's very little in the way of long-term understanding of the health risks by either Health Canada or the U.S. Environmental Protection Agency.

“There are no national standards that detail how clean is clean enough for a residential home damaged by a nearby fire,” Associated Press reporter Rebecca Boone wrote in an article about the concerns raised by Maui residents after a wildfire destroyed much of the town of Lahaina last summer.

“After a major wildfire burned 1,000 homes in Boulder County, Colorado, in 2021, health officials learned that even professionally remediated homes were often still polluted with ash, char and other toxic substances long after the fire,” Boone wrote.

READ MORE: Maui residents wonder if their burned town can be made safe. The answer? No one knows

A Kelowna-based air quality inspection company who didn't want to be identified told restoration companies do test for mould and toxins after they have finished the job but those tests are not always definitive.

Independent follow-up tests can be booked but those cost more than $1,000 each to test for either mould and mildew or toxins.

One detailed source of information on just how deadly house fires can be is The Red Guide to Recovery that has a detailed article about smoke particulates.

While asbestos, lead and mould are common “special care is given to be sure every microscopic fibre, spore and bacteria is removed,” the article by Sean M. Scott says. “This is done through extensive cleaning, HEPA (High-Efficiency Particulate Air) vacuuming, chemical applications, negative air and other procedures.

“Once the remediation is completed, an independent environmental testing laboratory or industrial hygienist provides an air clearance test to certify that the abatement or remediation process was successful. Upon receipt of the clearance, people can then re-enter the remediated area, rooms, or building.”

Such tests are rarely performed.

READ MORE: Okanagan, Shuswap home survived the fire? Now the work begins

Fire insurance often covers the cost of restoration, which includes the follow-up testing by restoration companies but not, generally, the added cost of independent environmental tests, Raymond Monteith, a senior vice-president for HUB International, told, who cautioned homeowners to deal with established restoration companies.

"There’s no question, especially after a wide impact event, it’s not unusual to see companies suddenly springing up and offering to provide these services and promoting themselves as restoration companies," he said. "They may or may not have the appropriate skills required to do the job. It's up to who you’re dealing with to ensure they do the quality of  work that is required."

Is there really cause for concern?

“A typical structure fire may generate literally tens of thousands of toxic chemicals and gasses,” Scott wrote in the Red Guide article. "Studies haven’t even scratched the surface to determine all the potentially adverse health effects that may result from exposure to the chemicals released from the combustion of the multitude of products in a structure fire.

"These include plastics, foams, textiles, carpets, wood products (treated lumber, plywood, flooring), synthetic fabrics, wool, electronics, furniture, household chemicals, and the list goes on. One of the biggest health threats from smoke is from fine and ultra-fine particles. These microscopic particles can penetrate deep into the lungs and can cause a range of health problems, from burning eyes and a runny nose to aggravated chronic heart and lung diseases and cancer. Exposure to particle pollution is even linked to premature death.”

Smoke toxins, he added, can be more hazardous to human health than things like mould, asbestos or lead.

The article goes on to list the health hazards of dozens of toxins, including benzene, arsenic, sulphur dioxide, hydrogen cyanide and formaldehyde.

“Respiratory ailments, cardiac hazards, and cancers connected with exposures to an environment affected by a fire are far greater than those from the past, mainly because the materials used today to manufacture our products and their chemical composition have changed dramatically,” Scott wrote.

Clearly, with wildfires becoming more prevalent with climate change, more research needs to be done to determine how safe it is to return home again.

“Health Canada has not developed guidance for residences impacted by house fires, in terms of procedures for removing carcinogens and determining removal effectiveness,” the email from Health Canada said.

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