Toxic algae bloom detected in Lake Lawrence

Thurston County Public Health and Social Services (PHSS) is reporting a toxic algae bloom in Lake Lawrence in Yelm.

Lab results taken from Lake Lawrence on Tuesday, May 12, detected microcystin toxin levels at 45.9 µg/L — nearly six times above the state recreation guideline of 8.0 µg/L.

Microcystins are a liver toxin and a possible human carcinogen. They can also cause illness in livestock and pets that drink affected water. 

“Staff will continue to collect weekly samples until they receive two consecutive weeks of samples with microcystin levels below state recreational guidelines,” PHSS said in a news release.

 “Even if the lake is visibly clear of algae, toxins may still be present,” PHSS advised. 

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. 

For more information about toxic algae blooms and health risks, and to see all Thurston County Algae Alerts, visit www.thurstoncountywa.gov/lake-alerts

Prior to Thursday's warning, Lake Lawrence's last algae bloom was detected in October 2025.