Keeping asbestos dust from spreading through a Calgary house during removal?

Keeping asbestos fibres contained during removal is a legal duty, not just a precaution. The Alberta OHS Code sets out exactly what a contractor must do, and the Alberta Asbestos Abatement Manual describes the practical steps that meet those requirements.

What the contractor is required to do

Before anyone touches the material, the contractor must file a 72-hour notification through Alberta's asbestos portal. No work that may release fibres can begin until that notification is made. Every worker who enters the restricted area must carry an original, valid Alberta asbestos worker card, issued after a government-approved course of at least 14 net instructional hours and a written exam with a pass mark of 80 per cent.

Once work begins, the OHS Code requires the employer to establish a restricted area: posted signs, no eating, drinking or smoking inside, protective clothing supplied, and a decontamination procedure before anyone leaves. The Manual scales the controls to the risk class. For high-risk work it describes an enclosure held under negative pressure, so air is drawn into the work area rather than out of it, until air tests confirm fibre levels are low enough to take the enclosure down. The Code's own requirement is that the methods used to decontaminate the work area, the workers, equipment and clothing prevent airborne asbestos as much as is reasonably practicable. Ask the contractor to describe, in writing, how that will be done in your house.

The risk class shapes how tight the containment needs to be. Removing a small area of intact vinyl floor tile with hand tools and water is low risk; removing friable material covering 0.09 square metres or more, or any work where the exposure limit of 0.1 fibres per cubic centimetre may be exceeded, is high risk and calls for a full enclosure held under negative pressure until air tests confirm fibre levels are low enough to dismantle it.

The Code requires waste in sealed, impervious, labelled containers, and the City of Calgary's rule for Shepard is material wetted before bagging, double-bagged in 6-mil polyethylene and sealed. In Calgary, asbestos waste goes to Shepard landfill only, by appointment made before 10 a.m. the day prior, with an Industrial Waste Permit in hand.

A few things worth asking before you sign anything:

• Will containment be set up before any material is disturbed, and will negative pressure be maintained throughout?
• Who does the clearance air testing, and is it an independent consultant rather than the abatement crew itself? The Manual describes final air results below 0.01 fibres per cubic centimetre for moderate-risk work, with aggressive sampling if a containment was used.
• Can you see the workers' original asbestos cards, not photocopies?
• Is disposal at Shepard included, and will you get the landfill receipt?
• Does the contractor have a WCB clearance letter and liability insurance you can verify?

Under Alberta's consumer protection rules, a prepaid contract of $200 or more must be in writing with itemized prices, a completion date and a statement of your cancellation rights; you can cancel within 10 days of receiving your written copy.

After the job is finished, keep the original bulk-sample lab report, a copy of the 72-hour OHS notification, the independent clearance letter with the air-test results, and the Shepard landfill receipt.

To hear from local abatement contractors, use the form on this page; your request goes to contractors listed in the Calgary Construction Network directory.