Founded in 1949, the Ontario Public Health Association (OPHA) is a voluntary, charitable, non-profit association. OPHA is an organization of individuals and Constituent Associations from various sectors and disciplines that have an interest in improving the health of the people of Ontario. The mission of the organization is to provide leadership on issues affecting the public's health and to strengthen the impact of people who are active in public and community health throughout Ontario.

The OPHA has several Workgroups composed of volunteers from across the province. One promotes breast-feeding, one focuses on child's health, and another addresses environmental health. The Environmental Health Workgroup has been active on issues related to air quality, pesticides, electromagnetic fields, water quality, food safety and children's environmental health.