Administator note: The Ministry of Environment, Conservation and Parks (MECP) provided the attached PDF on June 26, 2026. MECP provided this additional comment below on July 3, 2026. 

Note de l'administrateur : Le ministère de l'Environnement, de la Protection de la nature et des Parcs (MEPP) a fourni le fichier PDF ci-joint le 26 juin 2026. Le MEPP a fourni le commentaire supplémentaire ci-dessous le 3 juillet 2026. 

Please use the following wording as MECP's response:

Ontario noted that approved mixing zones are typically limited in extent, generally ranging from a few metres to a few hundred metres, except in limited circumstances. Mixing zones are established on a site-specific basis and must be kept as small as possible. They are not intended to serve as a substitute for reasonable and practical treatment measures and must not create conditions that are acutely lethal to aquatic life or result in irreversible environmental effects, as outlined in Procedure B-1-5.

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