Today, there are around 50,000 polluted sites nationwide. These include more than 4'000 contaminated sites, which in the short or long term pose a hazard to human health and the environment through the release of harmful substances. As this risk is not acceptable over the long term, the federal government has called for this undesirable legacy of past practices to be neutralized by 2025. In the remediation of contaminated sites, the federal authorities are guided by specific objectives concerning the protection of human health and by the extent of the hazard posed to environmental assets such as soil, air and water.