Answering your questions

Published: 21 March 2023

Dear members of the Macdonald Campus community,

Thank you to everyone who joined us for last week’s Town Hall. We have received quite a few questions, and we will answer as many as we can in the coming days in FAQ, with updates flagged by date.

Community members have asked why the building was shut down if air test results were never above the regulatory threshold, why dust tests were not re-performed, and why a positive wipe test triggered a building shutdown in this instance. Drawing on the expertise of McGill’s Environmental Health and Safety team, we have prepared some additional context.

First, it’s important to understand the different types of tests and how they are used:

  1. Bulk sampling
    Many buildings contain asbestos that is safely contained within building materials (e.g. in a closed wall). Asbestos fibres only become a concern if they become loose and airborne. McGill uses bulk sampling to test materials that are in poor condition (e.g. a broken tile) – if the material contains asbestos, it must be checked to ensure that it is intact and that asbestos fibres cannot be released. If it is not intact, it must be repaired or removed. If this cannot happen right away, the area must be sealed off until that work can happen.
  2. Dust sampling
    Dust sampling (e.g. wipe tests, microvac) is carried out in order to determine whether asbestos fibres have come loose, and can indicate whether further investigation may be needed. Under normal circumstances, a single positive wipe test is not cause to close a building – in part because these tests can note the presence or absence of asbestos but cannot indicate whether it exists in a concentration that poses health risks if airborne. A single asbestos fibre in dust collected from surfaces around a room will trigger a positive test result but does not necessarily indicate a safety threat.

    The building complex was closed on January 31, 2023, because of multiple concerns including the presence of dust apparently related to construction, and positive wipe and bulk sampling tests. Action needed to be taken in order to address these concerns.
  3. Air testing
    Air tests are the primary means used by the Government of Quebec to monitor workplace safety in construction situations where asbestos may be involved. Quebec’s Construction Safety Code (3.23.16 (12)) mandates that air tests must be under the threshold of 0.01 fibres per cubic centimetres after high-risk asbestos work is done. When McGill performs air tests, it requires that the tests meet this same threshold.

    Quebec's threshold in regular office/classroom situations is significantly higher (0.1 fibres per cubic centimetre), but McGill’s self-imposed threshold in all situations, applied as our safety standard across all University buildings, is the more stringent 0.01.

To address some of your questions about testing:

  • If air test results were within regulatory thresholds, why did the buildings close?
    The buildings closed due to a combination of factors: a positive wipe test; damaged building materials containing asbestos; and reports of dust apparently related to construction. Though air tests on February 1 and 2 produced results within the safety threshold of 0.01 fibres per cubic centimetre, the EOC ordered testing in every room in Macdonald-Stewart, Barton and the areas of Raymond that were accessible during the renovation work.
  • Would more dust sampling be useful?
    When dust sampled from surfaces shows the presence of asbestos, it is cleaned under the appropriate protocols. Afterwards, ongoing air testing is the best tool to determine whether any asbestos is introduced into the areas.

If you notice new dust accumulation or see damaged building materials, please call the Facilities Call Centre at (514) 398-4555 right away.

Thank you for taking the time to raise good questions – your concerns are entirely understandable, and we will do our best to continue addressing them via updates to this FAQ in the coming days. As Interim Principal Manfredi noted in his March 14 email message, it’s essential that we all gain the fullest possible understanding of this situation. We are working hard to ensure this happens.


Fabrice Labeau, Co-Acting Provost and Vice-Principal (Academic), Deputy Provost (Student Life and Learning) and Planning Chief for the Emergency Operations Centre (EOC) on behalf of the EOC

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