Condemned Fort McMurray properties could remain uninhabitable until September

More than 500 homesand a dozen apartment buildingsleft standing in the hardest hit areas of Fort McMurray have been declared uninhabitable, and could remain condemned until September.

With re-entry for thousands of evacuees set to begin on Wednesday, emergency officials have confirmed that access to Abasand, Beacon Hill and Waterways is restricted until further notice.

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Somestructuresmanagedtosurvivetheflamesintheseneighbourhoods,whichareamongthemostdamagedareasof the city.

Around2,000 people who live in these neighbourhoodswere getting ready to move back in on the weekend.

However, tests done in these areas confirm the soil and ash is heavily contaminated with chemicals like arsenic and other heavy metals. The unhabitable properties will not be deemed safe until all the debris is removed, a process which could take months.

I realize this will be difficult news for people to hear who were expecting to return to their homes later this week.- Premier Rachel Notley

"I realize this will be difficult news for people to hear who were expecting to return to their homes later this week," Premier RachelNotleysaid in a Monday news conference.

"But as always, safety and health remain our top priority."

For homes that have been structurally compromised, the municipality says it will make arrangements for residents to view their property safely, but more details will only be made available on re-entry.

"Damage assessments show that about 2,500 residences were lost, and these include single family, semi-detached, townhouses, apartments and potential basement rentals," Health Minister Sarah Hoffman said during an evacuee town hall last week.

"The majority of the homes are either livable or salvageable which is a tremendous achievement in the face of this wildfire."

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Residents who do return to the city are advised to take precautions when around ash or debris, such as wearing long-sleeved shirts, pants and gloves.

Meanwhile, homes destroyed by fire have been sprayed with a composite material that hardens into a protective shell, acting as a barrier keeping contaminated ash and other debris from spreading through the air.

The blanket prevents cross-contamination by wind that could pick up the toxic ash and spread it into uncontaminated areas.

Health risks 'can be quite significant'

Provincial officials say the ash is heavily contaminated concentrationsof cancer causing agents such as polyaromatic hydrocarbons, dioxins and furans have been detected at levels unsafe for human exposure.

"The health risks can be quite significant," said Paul Jones, professor andCanada Research chair in environmental toxicology.

"A lot of the ash from wildfires, particularly those that burn human residences and the like, those ashes can contain heavy metals as well other organic chemicals as well."

Jones says the powerful chemistry of the wildfire is to blame for making the aftermath so toxic.

"It's what we call an uncontrolled combustion," Jones said.

Because there is usually insufficient oxygen present, Some strange chemical reactions take placeso we get all kinds of chemicals generated with the burning of those materials, as well as we get lots of ash and soot because they don't burn completely."

The staged re-entry plans for the rest of the 90,000 evacuees is on schedule to begin Wednesday.

The fire is still burning, covers just under 580,000 hectares, although it is not expected to grow significantly in the coming days as damper conditions provide some much-needed relief to the 2,000 firefighters now battling the blaze.