the risks of removing asbestos containing drywall October 29, 2011

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1 Summary of recent research about the risks of removing asbestos containing drywall joint compound during residential renovation Presented by David Redmond October 9, 011

2 Some background information about asbestos-containing t i drywall joint compound (ACDJC) Prior to the early 1980s, asbestos was universally used in drywall joint compound (also called mud or mastic). The asbestos content of the drywall joint compounds usually ranged from 3% to 6%. The overall asbestos content of the composite wall system by weight is about 0.5% including the weight of board. In 1980, use of asbestos in building products was banned by the Canadian Hazardous Products Act.

3 Two factors that mitigate the level of risk associated with asbestos-containing drywall joint compound 1. ACDJC contains chrysotile asbestos, the less dangerous of the two forms of asbestos. Chrysotile asbestos is less persistent in lung tissue and low level, intermittent exposure is not a health risk to a healthy person. The most dangerous types are the forms comprising amphibole asbestos, which was not widely used in building products.. ACDJC is non-friable, meaning that it is a more durable material held together by a binder (latex) and is not easily crumbled or broken up. ACDJC is not friable because of the use of latex in the original formulation. It is very hard, quite dense, adhered to drywall one side and usually painted on the other side.

4 The Issue the risks to health of renovating homes with asbestos-containing t i drywall joint compound (ACDJC) Everyone agrees that asbestos can pose serious health risks when individuals are exposed to airborne fibres. When not disturbed, asbestos-containing drywall joint compound poses little or no risk because it is stable and does not release dust or fibres. During home renovation, the drywall may be cut, broken, sanded or otherwise manipulated. The key questions: Do home renovation activities release asbestos fibres from ACDJC? If yes, what are the health risks to workers and occupants?

5 Advice and Guidance to Consumers from Government tagencies CMHC: People can put themselves at risk if proper precautions are not taken during repairs or renovations involving asbestos-containing materials. One risk identified is sanding or scraping older water-based asbestos coatings including drywall. Health Canada: To minimize risk of inhaling airborne asbestos, homeowners should receive expert advice before removing any materials that may contain asbestos. If handling small amounts of damaged asbestos-containing materials, homeowners should follow a series of steps including sealing off the work area, wetting the material, avoiding cutting, breaking or damaging the material, wearing protective clothing including a single-use respirator, sealing the waste in plastic bags, and disposing of the waste according to municipal regulations. US Environmental Protection Agency: Asbestos in Your Home website identifies drywall joint compound as a common product in older homes that contains asbestos. DIY repair or renovation involving asbestos-containing materials is not recommended. Both major and minor repairs involving asbestos-containing materials should be done by professionals.

6 Provincial regulation of asbestos-containing drywall joint compound Some provinces classify ACDJC as a Low Risk (Type 1) product, requiring ii normal ldust control: Saskatchewan Manitoba Quebec The Maritime provinces: Nova Scotia, New Brunswick, PEI Other provinces classify it as a Moderate Risk (Type ) product: British Columbia Alberta Ontario Newfoundland and Labrador

7 What does regulatory classification as Type Moderate Risk mean for ACDJC removal? For the work area: a marked off area with warning signs dust enclosures such as drop sheets, sealed windows and doors isolation of the HVAC system use of a wetting agent cleaning with a HEPA-filtered vacuum or by wet sweeping or mopping disposal of all materials/waste in containers defined by regulation For the worker: protective clothing impervious to fibres use of a respirator rigorous clean-up while wearing respirator suit clean-up and removal

8 Why does this issue matter to the residential renovation industry? The types of ACDJC removal procedures prescribed by provincial regulation can have a very large impact on the costs of renovation. It has been estimated that the requirement for Type removal procedures can add $1,000 to $15,000 to the demolition cost of a typical residential home in Ontario and $7,000 in Newfoundland. The total construction cost impact in Ontario has been estimated to be over $15 billion.

9 What tests are used to determine if home renovation activities iti release asbestos fibres from ACDJC? Understanding the different testing methods is critical to the assessment of the risks associated with ACDJC removal. There are two main types of tests for measuring asbestos in air samples: 1. Phase Contrast Microscopy or PCM, which uses a light microscope.. Transmission Electron Microscopy or TEM, which uses an electron microscope. The PCM test is less sensitive: it detects all fibres but cannot distinguish between asbestos and other fibres. The TEM test can distinguish asbestos and all other types of fibres.

10 Additional information about the testing methods for detecting ti asbestos fibres PCM - Phase Contrast Microscopy (NIOSH* 7400): The PCM test is a method that uses magnification. The PCM test detects all airborne fibres that meet specific shape, length, width and aspect ratio (the ratio of the longer dimension of a shape to its shorter dimension). The PCM method cannot distinguish between asbestos and non-cancerous building materials. Some gypsum crystals can be counted in the same category as asbestos fibres. The PCM method is the least expensive testing method. TEM - Transmission i Electron Microscopy (NIOSH 740): In TEM asbestos testing, magnification and chemical and mineral tools are used to determine the difference between asbestos and non-asbestos materials. The TEM method counts only asbestos fibres of the same size and shape criteria, excluding, for example, gypsum crystals. TEM is the most expensive form of testing. The National Institute for Occupational Health and Safety (NIOSH) is the U.S. federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness.

11 Comparison of TEM and PCM methods by testing ti labs Independent laboratory testing confirms that TEM is required to distinguish asbestos from other fibres in airborne samples. High fibre counts using PCM testing do not necessarily indicate the presence of asbestos. PCM is widely used to measure fibre concentrations in air samples and is routinely used at asbestos abatement sites because of the fast turnaround and low cost.

12 Research related to ACDJC removal conducted d in Canada Pinchin Environmental Ltd. has conducted field tests at over 0 sites in Ontario and Newfoundland to determine airborne asbestos exposure in drywall removal. They removed drywall with ACDJC in a sealed envelope using worst case scenarios to increase the amount of dust released. Air samples were tested using both PCM and TEM methods. The results for all samples tested t showed: 1) higher h asbestos fibre counts with the PCM tests; and, ) counts below the limit of detection of asbestos with the TEM test. Pinchin Environmental concluded d that t "virtually all the airborne fibres are not asbestos and that the removal of ACDJC does not produce any significant level of airborne asbestos."

13 Research related to ACDJC removal conducted d in the U.S. Three U.S. Studies published in peer reviewed journals have produced similar results and draw conclusions similar to those of the Pinchin Environmental research in Canada: 1. Demolition ofgypsum Wallboard withasbestos Asbestos Containing Mastic (00) Controlled laboratory tests and field tests of two actual demolitions foundthat manyfibres were detected using PCM testing. Subsequent TEM testing found that almost none of these fibres were asbestos.

14 Research related to ACDJC removal conducted d in the U.S. (cont.). Occupational exposure to airborne asbestos from coatings, mastics and adhesives (004) Air samples taken in a lab following five different actions on ACDJC, including cutting and removal, found almost no detectable asbestos using TEM testing and little health risk from occupational exposure. 3. Asbestos release from whole building demolition of buildings with asbestos containing material (007) In a whole building demolition test of buildings with asbestos containing materials, air sample monitoring and PCM testing found that the concentrations of fibres were generally below the permissible exposure limits for workers. Subsequent TEM testing found that most of the fibres detected were not asbestos.

15 Summary and conclusions Use of incomplete testing methods is a contributing factor in the overestimation of the risks associated with removal of ACDJC in some provincial regulation. Tests conducted in Canada and the U.S. by experts and environmental professionals consistently show that renovation-related activities involving ACDJC release asbestos fibres in negligible quantities that are well below the thresholds of risk to worker or occupant health. These experts and professionals conclude that TEM currently is the only valid method of testing for determining exposure to airborne fibres during the removal of asbestos. The recent research about testing methods, and the results of field and lab tests about the risks associated with the removal of ACDJC during renovation, should be considered in the review of any regulatory proposals.