​ This document is intended to support planning for boards of health and public  health units (PHUs) in Ontario. Other levels of government and potential partners  may also choose to use the guidance contained in this document. It includes ​

Governance: roles, responsibilities, and decision-making structures ​

Triggers for the issuing of various heat warning to the public health units from a  central source, and mechanisms for disseminating these warnings ​

Definitions of warnings, along with suggested core activities ​

Communications messaging to support the various warning levels ​

Planning guidance to support the public health units and local partners in their  heat response planning