Harmful Algae Blooms


Harmful algae blooms (cyanobacteria), also known as blue-green algae or pond scum, form on lakes and can create toxins that are harmful to humans and animals. 

Residents of a lake with a harmful algae bloom may be affected depending on their closeness to the site of the algae, the size of the lake, wind directions, water flow, and other environmental conditions that cannot be predicted or controlled. Due to the many factors involved, government authorities are unable to determine where and when there are no toxins. Users are recommended to use their judgment. For further details on the location of the algae bloom, contact the Ministry of the Environment, Conservation and Parks - Spills Action Centre - 1-800-268-6060.

 If you reside near where the bloom was detected or are visiting the lake and encounter the algae, follow these safety measures:

  • Do not use the water. This includes: drinking, cooking, bathing, and brushing teeth. Note: Using a private water system or boiling the water will not destroy the toxins.
  • Do not swim and avoid water sports where there is harmful algae.
  • Limit the amount of fish flesh you eat. Some toxins can build up in fish and shellfish. Do not eat the liver, kidneys and other organs. Be careful not to cut the organs when filleting.
  • If skin contact does occur, wash with soap and water or rinse thoroughly with clean water to remove algae.

 More information about cyanobacteria (harmful algae bloom) found here.

Algae Sample Locations

September 21, 2018
Map of the sample location of the harmful algae bloom in the western area of Deer Lake
September 19, 2018

Tilden Lake

Map of the harmful algae bloom sample location on Tilden Lake. The map demonstrates that the sample was taken from the southern part of lake.

September 18, 2018
September 13, 2018
August 16, 2018

Ontario's 12-point plan on harmful algae blooms

Ontario is concerned about the effects of harmful algae blooms in our water.  Ontario has a 12-point plan outlining how we are working with our many partners, to fight algae blooms in the Great Lakes and other lakes and rivers. 

For more information on Ontario's 12-point plan on harmful algae blooms click here.

Canada's drinking water guidelines during harmful algae blooms

Health Canada and the Federal-Provincial-Territorial Committee on Drinking Water are updating advice for parents of young infants when it comes to using tap water to prepare infant formula during harmful algae blooms.

For more information on Canada's drinking water guidelines during harmful algae blooms click here.

More information about blue-green algae

Things you should know about harmful algae blooms (HAB)

North Bay

345 Oak Street West

Parry Sound

70 Joseph Street Unit #302

Burk's Falls

17 Copeland Street (by appointment only)