Two other children remain on ventilators at the Stollery Children’s Hospital in Edmonton.
All four children, along with their eight-month-old sister who died, were exposed to the illegally imported pesticide when their mother placed phosphine tablets around their Fort McMurray apartment last week.
The children were taken to hospital on Sunday, and the infant died in hospital the next day.
The mother, who was also taken to hospital to be monitored, has since been released.
The pesticide was brought back to Canada from Pakistan by the family on a recent trip.
The family's lawyer provided a brief statement, thanking people for their support.
"The Habib family requests that their privacy be respected as they grieve their loss and prepare for the funeral of their youngest child. Thank you to all for your support during this trying time," said Allan Vinni, who specializes in real estate, immigration, litigation, criminal and family law.
Community rallies to raise money
Once the two children are released in Fort McMurray, their mother plans to gather the family's possessions from their apartment and travel to Edmonton, where the children's father already is.
Meanwhile, a GoFundMe webpage for the Habibs has so far raised more than $16,000.
Organizer Niola McLean said she created the crowd-funding page on Wednesday after seeing some hateful messages posted about the family's situation on social media.
"I have four children of my own and everybody makes mistakes. It just broke my heart hearing what had happened and having to live with that for the rest of your life," she said.
McLean visited the children's mother in the Fort McMurray hospital on Wednesday evening to tell her about the web page.
"The poor mom — she just looked shell-shocked. I just feel so bad. No one wants to go through that."
McLean also met the two children, aged four and seven, and reported that they were in good condition.
She plans to leave the GoFundMe page open for now in the hopes that more money can be raised for the family.
"Now they have a funeral, they've got the children who need a new place to live, they need clean furniture," she said. "They can't go back there."
Monitoring air quality closely
Crews continue to monitor air conditions in the Habib family apartment, where trace elements of phosphine still linger.
"What we did find is throughout specific parts of the one bedroom, more in the low-lying areas, in the closet areas and more dead space areas, we did find some higher elevated levels, so we're just basically in precaution mode right now," said Brad Grainger, the deputy chief of operations for regional emergency services.
Grainger said his crew will reseal the apartment and return again on Thursday to test once more.
He noted that the levels measured do not indicate any danger for his crew or for other residents in the building.
About phosphine:- A clear, colourless gas classified by WHMIS as "very toxic."
- Typically combined with calcium or aluminum into tablets when used as a fumigant.
- Tablets react to moisture in air and give off gas.
- When inhaled, phosphine causes cell damage in lungs and acts and affects the nervous system.
- In Canada, phosphine is used in grain storage but must be administered by trained users.
- Outside of Canada, phosphine has been approved for use in other contexts.