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Blue-Green Algae

Blue-green algae blooms are a natural seasonal phenomenon that may appear in lakes, rivers and ponds. Some species have the potential to produce toxins which may be harmful to people and animals. Toxins are released into the water when the algae cells are damaged or begin to decay. Direct contact with the toxin can cause skin irritation and if ingested in higher concentrations, may result in vomiting, nausea, diarrhea and abdominal pain.

The Porcupine Health Unit asks residents to monitor area waters and if an algae bloom is present, please take these precautions and report the bloom to the Ontario Ministry of the Environment, Conservation and Park's Spills Action Centre at 1-800-268-6060.

  • Use an alternate source of water; boiling the water or using home water treatment devices will not destroy the toxins.
  • Do not use the water for drinking or for food preparation including infant formula;
  • Avoid using the water for washing dishes and clothes; 
  • Avoid eating fish caught from areas where an algae bloom is present; 
  • Use of the water is not recommended for animals; pets and livestock can also be affected; and
  • Avoid swimming and other water sport activities that could increase the risk of ingestion and/or skin contact as the toxins can irritate the skin.

Watch this video: What causes blue-green algae blooms?

Current waterways affected by blue-green algae


Affected Waterway Municipality Date Public Notice Issued
Star Lake Timmins June 19, 2023
Horwood Lake Sudbury District (Penhorwood Township) July 14, 2023
Nellie Lake Iroquois Falls August 17, 2023
Driftwood River Shillington (Stock Township) August 31, 2023
Watersnake Lake Fauquier-Strickland (Shackleton Township) September 16, 2023
Lake Ste. Therese Hearst (Casgrain Township) September 18, 2023
Remi Lake Moonbeam (Fauquier Township) September 21, 2023


Affected Waterway Municipality Date Public Notice Issued
Wildgoose Lake Black-River Matheson August 11, 2022
Star Lake Timmins September 14, 2022
Painkiller Lake Black-River Matheson September 15, 2022


Affected Waterway Municipality Date Public Notice Issued
Kenogamissi Lake Timmins June 21, 2021


Affected Waterway Municipality Date Public Notice Issued
Remi Lake Moonbeam June 2, 2020
Big Water Lake Timmins June 29, 2020
Munro Lake Black-River Matheson July 8, 2020
Confluence of Black River and Driftwood River Iroquois Falls July 23, 2020
Maloney Lake Cochrane August 25, 2020
Wabbler Creek Val Gagne September 11, 2020

For more information, see the Government of Ontario Blue-green algae page.