The Ontario Ministry of Labour has identified a number of contaminants as particularly troublesome and has listed theses as "designated substances" under the Occupational Health & Safety Act. Among these are two substances commonly found in older buildings; asbestos and Lead.
Lead-based paints were commonly used up until the mid-1950s and many buildings have these present. Lead is a contaminant which is particularly dangerous for young children who may chew on lead painted surfaces such as window-sills. A&A can conduct an assessment of your building for lead based-paints.
The use of asbestos in building construction materials has been widespread throughout most of the twentieth century but it is now clearly linked to certain types of human cancers such as mesithelioma and so the allowable levels of airborne asbestos in the workplace are now strictly controlled. Its chemical and fire-resistance properties were put to full use in insulation materials such as pipe-wrap and boiler insulation and construction materials such as wall board, siding, roofing, floor tiles etc. Recently it has been discovered about 2/3rds of the "Vermiculite" insulation used in Canada carries high levels of asbestos fibres. As a result, many residences and commercial buildings built before the mid 1980s have asbestos containing materials within them and this represents a serious health concern to the occupants, particularly if the asbestos containing materials are disturbed during renovations or repairs. In 2005 Ontario enacted Regulation 278/05 under the Occupational Health & Safety Act requiring that all renovations on buildings be preceded by an asbestos assessment. A&A can conduct this type of assessment and organize the removal of asbestos materials from your building should this be necessary.