Health officials are urging people and pets to avoid areas of Tanwax Lake in Pierce County where visible algae blooms are present, following a toxic algae caution advisory Friday.
The Tacoma-Pierce County Health Department (TPCHD) warned after algae was found in the lake during a sampling on Oct. 15.
Signs have been posted at the lake to alert the public to the potential health risks. The department advises avoiding swimming, wading, waterskiing, or fishing in areas where algae is visible.
Officials also cautioned that wind conditions can move the algae to different parts of the lake.
“We will inspect the lake again next week,” TPCHD said in the advisory, adding that updated information about water conditions can be found on the department’s website.
Toxic algae, also known as cyanobacteria, naturally occur in lakes but can produce harmful toxins that pose a risk to humans and animals.
The algae can appear as a scum layer resembling green pea soup, streaks, clumps, or dispersed throughout the water. It can vary in color from green to brown, red, or even blueish, depending on wind and weather conditions.
Health symptoms associated with toxic algae exposure can include muscle weakness, vomiting, diarrhea, and nausea.
In severe cases, it can cause skin irritation and rashes. Pets are especially at risk due to their smaller size and the likelihood they may ingest algae-tainted water while grooming themselves.
If exposure occurs, health officials recommend rinsing off immediately and seeking medical attention if symptoms develop.
For pets, owners should keep them from licking their fur and seek veterinary care at the first sign of illness.
Residents are advised to avoid consuming fish from areas of the lake affected by algae and to follow guidelines for reducing nutrients that fuel algae growth, such as minimizing fertilizer use and properly disposing of pet waste.