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August 17, 2021

Immediate closure of Pass Lake: Danger for toxic blue green algae exposure at Pass Lake, Deception Pass State Park

Users of Deception Pass State Park should be aware that Pass Lake in the Skagit County portion of the park is closed until further notice due to high Anatoxin-a levels. Water samples tested this week detected concentrations of Anatoxin-a in exceedance of the state recreational guidelines.

The preliminary result from the King County Environmental Lab is 2,576 micrograms per liter of anatoxin-a present in the water sample taken from Pass Lake. According to the Washington State Department of Health, the level of public health concern for anatoxin-a is 1 microgram per liter. 

Anatoxin-a is an acute neurotoxin that can be harmful to humans and animals. Even short-term exposure is a concern. Signs of Neurotoxin Poisoning appear within 15-20 minutes of ingestion, and may include:

  • In people: numbness of the lips, tingling in fingers and toes, and dizziness.
  • In animals: weakness, staggering, difficulty breathing, convulsions, and death.

Until further testing confirms the toxin levels are back within state recreational guidelines, red “Danger” signs will be posted at the lake advising individuals to keep out of the lake, do not swim, drink lake water, fish, recreate, or allow pets or animals to access the lake.

The toxicity of each bloom can vary and is difficult to predict. Toxicity can change from one day to the next. It isn’t possible to determine how dangerous a bloom is to people and animals by looking at it. Only testing can tell if it is dangerous. Pass Lake will be continuously monitored until the levels drop below recommended guidelines.

The public is encouraged to take the following precautions when choosing a body of water for recreation:

  • Contact a healthcare provider immediately if you become ill or have symptoms after a suspected exposure to algae bloom.

For questions concerning cyanobacteria blooms within Skagit County lakes, please e-mail Samantha Russell at eh@co.skagit.wa.us or visit the Washington State Department of Health website for Blue-Green Algae. Testing results for Washington Lakes are posted at Washington State Toxic Algae.