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Toxic Blue-Green Algae (Cyanobacteria) in Timnath Reservoir

September 13, 2023

Town staff has confirmed Toxic Blue-Green Algae (Cyanobacteria) in Timnath Reservoir. We ask that you and your pets stay out of the water at this time. Blue-green algae can be harmful to you and your pets. The Reservoir will remain open for boating and fishing, but the Colorado Department of Public Health and Environment advises against using the water for recreational purposes.  

Toxic algae or harmful algae blooms (HAB) are made up of what many people call blue-green algae. Technically, these organisms are a particular type of bacteria called cyanobacteria or cyanoHABs. Although these organisms naturally occur in Colorado waters, they become problematic when they multiply rapidly, resulting in a dense cyanobacteria concentration or “bloom.” The blooms become harmful when the cyanobacteria produce toxins. We have confirmed the presence of toxins related to blue-green algae.

Direct contact can cause health issues in humans and animals. It is recommended that people and their pets avoid contact with the algae. Exposure may also occur through other routes, such as inhalation, dermal exposures, or by consuming fish from cyanotoxin-contaminated waters that are not properly cleaned and gutted. Cyanotoxins become aerosolized during activities such as water skiing, which can be inhaled during those activities.

To protect yourself and your pets:

  • Avoid contact with blue-green algae blooms.
  • Keep children away from algae and scum in the water along the shoreline.
  • Do not swim or wade in water where blue-green algae is visible.
  • Do not allow pets to enter or drink the water.
  • If contact occurs, wash with clean water as soon as possible.
  • Call your doctor or veterinarian if you or your animals have sudden or unexplained sickness after being at the Reservoir.