What if an Alberta asbestos lab report says trace amounts?

What "Trace" Means on an Alberta Asbestos Report

A result reported as "trace" or "less than 1 per cent" on a polarized light microscopy (PLM) bulk sample report means the lab detected asbestos fibres but at a concentration too low to quantify precisely. The Alberta Asbestos Abatement Manual describes PLM as reporting results from 1 to 100 per cent, with anything below that threshold recorded as less than 1 per cent. Trace is not zero, and it is not a clearance.

What matters next is what you plan to do with the material. Health Canada advises that undisturbed material in good condition, sealed behind walls or floors or isolated in an attic, presents no significant health risk. If the material stays put and no renovation touches it, a trace result may require no immediate action. If you plan to cut, sand, break or remove it, settle how it will be handled before anyone starts. The Alberta OHS Code's 72-hour notification requirement applies to any employer removing or abating asbestos-containing material before activities that may release fibres, with no minimum quantity threshold. A trace result does not exempt a contractor from that obligation.

The risk class the contractor assigns matters too. The Alberta Asbestos Abatement Manual describes low, moderate and high risk categories based on how likely the work is to generate airborne fibres. A trace result in a non-friable material handled without cutting or breaking may fall into the low-risk description, but the same material drilled, sanded or demolished can move into moderate or high risk. Ask the contractor to explain in writing which risk class they are assigning and why, because that decision drives containment, air monitoring and clearance requirements.

A few things worth confirming before any work proceeds:

• Ask whether point counting was done. The Manual says point counting gives a more reliable quantification than a standard PLM estimate.
• Confirm the lab participates in a proficiency testing program. Alberta law does not require lab accreditation, but the Manual describes participation as best practice.
• Ask for the clearance standard the contractor will meet. 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; for low-risk work it expects monitoring to stay below that level during all phases.
• Ask whether clearance sampling will be done by a consultant independent of the abatement crew, and which lab will count the samples.

On disposal, Alberta's asbestos disposal guidelines define asbestos waste as material with more than 1 per cent asbestos by weight, and a result below 1 per cent sits under that line. The Alberta OHS Code has its own definition, which binds the contractor's handling: material discarded because there is a reasonable chance that asbestos might be released from it and become airborne. That definition turns on release, not on a percentage, and the Code requires such waste in sealed, impervious, labelled containers. Ask the contractor and the landfill how they will classify the debris before anything is binned. Material handled as asbestos waste in Calgary goes to Shepard landfill only, with a permit and appointment, wetted, double-bagged in 6-mil polyethylene and sealed, at $220 per tonne.

You can submit the report details through the request form on this page and local abatement contractors listed in the Calgary Construction Network directory will respond by email.

The question that saves the most confusion later: is clearance air testing in the quoted price, or billed separately afterwards?