WINTER 1998     Inside: • MOULD — A Growing Health Concern in Buildings • Using Geophysics for Site Characterization • Bow Valley Centre Demolition • Occupational Ergonomics • Interactive Multimedia BOW VALLEY CENTRE DEMOLITION By Chris J. Jodouin, B.Sc., CIH     On October 4, 1998, a Calgary landmark was reduced to a pile of rubble in a matter of seconds. Several high-rise buildings which made up the Bow Valley Centre (formerly known as the Calgary General Hospital), was demolished by implosion, a process whereby the structural supports are suddenly weakened and the buildings fall upon themselves.     PHH Environmental, working on behalf of Alberta Public Works, Supply & Services (APWSS), participated in the pre-demolition and demolition phases by providing consulting and testing services related to the removal of hazardous materials, environmental monitoring of the implosion and participation in public meetings.     Prior to the implosion, hazardous building materials and other substances had to be removed from the structures and shipped for proper disposal. Two different contracting firms, over a period of twelve months, completed extensive asbestos removal work from this very large (900,000 square foot) complex. Abatement crews, working in several areas concurrently, numbered over 60 personnel during peak asbestos removal activity. The PHH Environmental team provided inspection, air monitoring and analytical services during all phases of asbestos abatement. PHH also assisted technical personnel from APWSS with the identification of asbestos-containing materials in enclosed/concealed spaces. Extensive demolition of partition walls, ceilings, and pipe/utility chases was undertaken to access these materials. PHH also provided inspection services related to the identification, packaging and transportation of other hazardous materials, including PCB’s from fluorescent light ballasts and other electrical equipment, CFC’s, mercury and radioactive sources from smoke detectors.     PHH was also active during the implosion event, during which we conducted environmental monitoring in the community surrounding the Bow Valley Centre. Air monitoring was conducted for: total suspended particulate (TSP), respirable particulate (PM10), lead, and asbestos. Settled dust was also sampled and analyzed for lead content using a portable Pace Scan ™ analyzer. 9:07 a.m., October 4, 1998. --     The demolition project raised many concerns for nearby residents. PHH participated in public meetings, along with representatives of the provincial government and the City of Calgary to discuss environmental aspects of the demolition and to answer the public’s questions.     The successful demolition of the Bow Valley Centre was the result of the co-operation and thousands of hours of co-ordinated effort from several organizations. PHH was pleased to work closely with APWSS; two abatement/demolition firms (McColman & Sons and Dewar Western); planning, fire and police officials from the City of Calgary; Alberta Environmental Protection; public health officials (CRHA); community representatives; and numerous sub-contractors. 9:08 a.m., October 4, 1998. --     Clean-up operations at the demolition site will be completed in the spring of 1999. The demolition contractor will haul about 7000 loads of rubble from the site. PHH will continue periodic environmental monitoring in the surrounding community during that time.