The Safe Environments Directorate (SED) wishes to establish various Standing Offers on a range of risk assessment activities to support its mandated roles to protect the health of Canadians from hazards posed by chemical substances, including air and water contaminants, novel substances and contaminated sites through risk assessment. The main purpose of the standing offer is to obtain a list of qualified companies that have a broad range of expertise in the area of human health risk assessment and provide scientific services which may include gathering scientific information for conducting a human health risk assessment, development of methodologies and tools for human health risk assessment, providing scientific expertise and training on human health risk assessments, conducting human health risk assessments (may include exposure assessment or hazard characterization), scientific peer review of assessment reports or scientific manuscripts and consultations on scientific issues relating to the conduct of human health risk assessment of chemicals, air and water contaminants, novel substances and contaminated sites.