Submitted by Thurston County
Thurston County Public Health and Social Services is reporting a toxic algae bloom for McIntosh Lake. Lab results from a sample collected from McIntosh Lake on July 30, 2025, detected Microcystins toxin levels at 9.2 µg/L, which is ABOVE the state recreation guideline of 8.0 µg/L.
Microcystins are a liver toxin and possible human carcinogen. Microcystins can also cause illness in livestock and pets that drink affected water. When an algae bloom is present, health officials recommend taking extra precautions to avoid the health risks posed by potential toxins.
- Do not drink the lake water.
- Avoid contact with water containing algae.
- Avoid swimming, wading, windsurfing, and water-skiing in waterbodies where algae blooms are present.
- Keep pets and livestock away from where algae blooms are present.
- Do not eat fish that come from the lake during an algae bloom.
- Avoid areas of scum when boating.
Staff will continue to collect weekly samples until they receive two consecutive weeks of samples with microcystin levels below state recreational guidelines. Even if the lake is visibly clear of algae, toxins may still be present.
For more information about toxic algae blooms, health risks, and Thurston County Algae Alerts visit the Thurston County website.
