A public health warning has been issued for Seabreeze Lake after harmful algae and microcystin toxins were detected in the water. Residents and visitors should avoid all contact with the lake until authorities confirm that conditions are safe.

People should not swim, wade, kayak, fish, or allow children to play near the water while the advisory remains in effect. Pets must also be kept away and should never be allowed to swim in or drink from the lake.

What are harmful algal blooms?

Freshwater harmful algal blooms are often caused by cyanobacteria, commonly called blue-green algae. These organisms occur naturally, but under favorable conditions they can multiply rapidly and form thick blooms, surface scum, floating mats or discolored water.

Some cyanobacteria produce toxins known as cyanotoxins. Microcystins, which the posted Seabreeze Lake notice says have been detected, primarily affect the liver and can make people, pets, wildlife and livestock seriously ill.

However, appearance alone cannot determine whether a bloom contains toxins. Water that looks relatively clear may still contain cyanobacteria or toxins, while some harmless aquatic growth can resemble a dangerous bloom. Laboratory testing is needed to determine the actual risk.

What causes a bloom?

Harmful blooms are more likely to develop when several conditions occur together:

Warm water and sunny weather

Slow-moving or stagnant water

High concentrations of phosphorus and nitrogen

Runoff containing fertilizers, animal waste or decomposing vegetation

Organic material accumulating in or near the water

Low water levels and limited circulation

Operating a large chipper and wood-waste storage site next to a lake creates an unnecessary water-quality risk. Rainwater flowing through piles of wood chips and decomposing vegetation can carry organic matter, tannins and other dissolved substances toward the lake, potentially increasing bacterial activity, lowering dissolved oxygen and creating conditions that favor harmful algal blooms and fish kills.

CDC findings

The CDC reports that toxin-producing algae are more likely to grow in warm, nutrient-rich water. Preventing recurring blooms therefore requires more than treating visible algae—it also requires identifying and reducing the nutrient sources feeding the bloom. CDC: Contributing Factors and Impacts

The chipper site next to the lake adds additional nutrients to the lake when positioned so close to the lake.

Health risks to people

People can be exposed by swallowing contaminated water, getting it on their skin or breathing airborne droplets produced by splashing or spray. Possible symptoms include:

Skin irritation, rash or itching

Eye, nose or throat irritation

Headache or dizziness

Nausea, vomiting or diarrhea

Abdominal pain

Weakness or difficulty breathing

Liver damage in serious cases

Anyone who comes into contact with the lake should immediately rinse their skin with clean water. Seek medical care if symptoms develop, and tell the healthcare provider about the possible exposure to cyanobacteria or microcystins.

Pets face an especially serious danger

Dogs are particularly vulnerable because they may drink contaminated water or swallow toxins while licking algae from their fur. Warning signs can include vomiting, excessive drooling, weakness, staggering, breathing difficulty, tremors or seizures.

If a pet enters the lake, keep it from licking its fur, rinse it thoroughly with clean water and contact a veterinarian immediately if exposure or illness is suspected. Cyanotoxin poisoning can progress rapidly.

Treatment does not mean immediate safety

The notice states that Seabreeze Lake will be treated with GreenClean Pro. Treatment may reduce algae, but residents should not assume the water becomes safe immediately afterward. Disturbing or killing cyanobacteria can release toxins from their cells into the surrounding water.

The lake should remain off-limits until follow-up testing confirms that toxin concentrations have fallen below applicable recreational-health guidelines and the public advisory has officially been lifted.

A warning about the lake’s long-term health

An algae bloom is more than an unpleasant surface condition. It can signal that the lake is receiving too many nutrients or that its ecological balance has been disturbed. Dense blooms can block sunlight, damage aquatic habitat and contribute to depleted oxygen as algae and other organic material decompose. Low oxygen can stress or kill fish and other aquatic organisms.

Protecting Seabreeze Lake will require continued monitoring, transparent reporting of test results and a long-term plan addressing nutrient inputs, shoreline vegetation, runoff, water circulation and nearby land-management practices.

Until officials declare the lake safe, the message is simple: stay out of the water, keep children and pets away, and report any suspected exposure or sudden illness to a doctor or veterinarian.

Washington residents can learn more or report a suspected bloom through the Washington Department of Ecology’s Freshwater Algae Control Program. Additional health information is available from the Washington State Department of Health.