Prior to planned renovation, demolition, or construction of an establishment, a Designated Substance Survey (DSS) is required to be conducted in compliance with the Ontario Occupational Health and Safety Act (OHSA). The OHSA and the ministry of labour stipulates that the presence of certain substances which deemed to be potentially dangerous to the workers and general public, be identified first, to allow construction workers to take precautionary measures in minimizing their exposure to these substances. Briefly, the designated substances in Ontario are the following: acrylonitrile, arsenic, asbestos, benzene, coke oven emissions, ethylene oxide, isocyanates, lead, mercury, silica, and vinyl chloride. The DSS report includes a thorough assessment of the presence, locations, and concentration amount of these designated substances in a construction or demolition site. With the right information on hand about these substances, the contractors will be able to take all the necessary measures to ensure the utmost safety and protection of their workers on site and the general public as well. In addition, the DSS report aids contractors and property owners alike to prepare well and avoid any unnecessary liabilities and compensation which may be incurred from getting exposed to these harmful substances.