Possible asbestos exposure at Edmonton school: What you need to know

Edmonton Public School superintendent Darrel Robertson apologized at a news conference on Friday after the board informed parents earlier this week that students may have been exposed to asbestos during construction work at a southside school earlier this year.

"We have broken some trust with our families. And we need to rebuild that trust. And that is ongoing work," Robertson told reporters.

The superintendent penned a letter to parents on Wednesday explaining the exposure happened at Greenfield School in May and June.

Testing found there were low levels (one to five per cent) of asbestos in drywall compound on drywall that was cut and removed from several classrooms after flood damage from a burst pipe.

A plastic sheet was the only barrier separating affected classrooms from the rest of the school.

Asbestos was commonly used in construction before 1990. It is safe if undisturbed, but if disturbed during construction or remediation, the particles can be inhaled into the lungs.

"The same thing that makes it so great makes it so dangerous because it doesn't break down," Moe Barzagar of First General Fire and Flood, which specializes in asbestos removal, told CTV News Edmonton.

"It has a barb-shaped fibre, so once you breathe it into your lungs, it hooks into your tissue and it won’t degrade."

According to the World Health Organization, the mineral is linked to a number of cancers, including lung cancer, mesothelioma, cancer of the larynx and ovary, and asbestosis (fibrosis of the lungs.)

Because of the health risks associated with asbestos, there are strict procedures required for remediating it.

"While the majority of our procedures were followed, the negative air pressure and containment we require in construction projects where asbestos-containing materials are present did not meet the division's standards," Robertson wrote in the letter.

"There is a possibility that low levels of asbestos-containing dust migrated into the hallway of the school across from the impacted classrooms between May 2 and May 9, and from June 5 to 6 when new drywall was being installed, which included trimming of the old drywall. "While it’s not possible now to verify if the dust contained asbestos, out of an abundance of caution, we are notifying families."

The board is encouraging parents to speak to their family doctor or pediatrician.

Before students returned to school this week, Robertson says the following cleaning procedures were implemented:

• a complete clean of the ventilation system;
• temporary walls have been put up to isolate the construction area;
• a deep cleaning of the school;
• all air filters (including HEPA filters) in the school have been replaced three times before students returned to school, including a filter change in early September;
• the highest level of compatible MERV filters have been used in the mechanical system, and the filters were changed in June, August and September before students returned to school;
• school air quality has been tested and is clear and will continue to be tested whenever work is being completed.

Robertson said repair work on the building is still underway, but will only take place on evenings and weekends when students are not present.

The initial work was performed by division staff.

The remaining work will be completed by an independent contractor under the supervision of independent hazardous material consultants.

"The repair area is completely sealed off with negative air pressure. Negative air pressure means that the contractor will isolate the air system in the room by creating a vacuum effect within the areas under construction. This ensures the air will not flow outside of the contained space," Robertson wrote.

"Additionally, contractors can only access the space from an external door.

"The mechanical system between the school and the area of construction has been isolated, which means that the rest of the school and the area that is under construction do not share airflow."

The work is scheduled to take another month to complete.

Robertson says the board is still in the process of conducting a thorough investigation with the help of an external investigator.

Occupational Health and Safety also conducted an investigation.

Parents can contact the Edmonton Public Schools division support services team at 780-429-8030 with questions about the exposure.

With files from CTV News Edmonton's Jessica Robb