Cyanobacteria, also known as blue-green algae, are bacteria which have some of the characteristics of plants. They are found throughout the world on land and in lakes, rivers, and ponds, and in estuaries and seawater (oceans). Thought to be caused in part by global warming, all over the world, more and more water bodies are seeing large areas of growth or algae blooms. These blooms are important because the bacteria produce toxins that affect water quality, ecosystem stability, surface drinking water supplies and public health.  

During early fall of 2021, portions of the shores of the Columbia River that flow through the Tri-Cities area (Richland, Kennewick and Pasco) were closed after the deaths of several dogs who had been exposed to toxic algae while along the shoreline.   

In Benton and Franklin Counties, BFHD was aware of this issue occurring in local lakes and rivers. What made this incident in 2021 unique was that toxin-producing blooms had not been found in the flowing waters of the Columbia River.  Of concern was that the area in which the blooms appeared to be occurring was the same area where the cities of Richland, Kennewick and Pasco have water intakes for their drinking water treatment facilities. BFHD works closely with these utilities to make sure that the drinking water is safe.

While not all algae blooms produce toxins, but there is no easy or quick way to know if a bloom contains harmful toxins. Activities that can expose you to toxic algae are swimming, boating or fishing. During these activities, exposure to toxic algae typically occurs when the toxins are swallowed, or one inhales water spray with the toxins.  By far, swallowing is the most common way to be exposed. 

Current Toxic Algae Updates on the Columbia River 

Update: September 15, 2023
ALL SITES WITH SIGNS: Howard Amon Swim beach Wade Park (Pasco) Leslie Groves Columbia Point

Benton-Franklin Health District (BFHD) sampling has detected extremely high concentrations of cyanotoxins (anatoxin-a) in algae mat material (clumps of algae) along the Columbia River. Clumps of algae tested showed levels of anatoxin-a approximately 50 times higher than the surrounding water.
Toxic algae blooms can poison animals, wildlife, and people. BFHD would like to caution animal owners to closely follow the advice below.

Recreational use of the water at any sites posted with a yellow warning or red danger signs should be avoided until anatoxin-a levels drop below recommended guidelines. These areas identified (Howard Amon Swim beach, Wade Park, Leslie Groves and Columbia Point) with signs are where we know there are current dangers, but we recommend being cautious everywhere along the shoreline.

When visiting a shoreline not under current warnings or restrictions, follow these guidelines if your pets go in the water:

  • Do not let them eat or chew on clumps of algae
  • Do not let them lick their fur
  • Rinse them with clean water after swimming
  • Rinse your hands and any exposed skin

BFHD has already received one report of a dog fatality from the week of 9/11. This incident prompted further testing of algae material after it was reported that the dog may have ingested the algae clumps. The death of this beloved pet is still under investigation, but out of an abundance of caution, we are taking swift action to prevent further fatalities.

The Benton-Franklin Health District extends our sincere condolences to the dog’s owner and their family. We hope this message may prevent other pet illnesses or fatalities through spreading awareness of the dangers of cyanotoxin poisoning. 

Animal Safety Graphic

Toxic Algae Warning Spanish

The Benton-Franklin Health District (BFHD) preliminary samplings have detected cyanotoxin (toxic algae) levels still above the recreational guidelines at the Howard Amon Swim beach. The most recent sample was analyzed and quantitated by the King County Environmental Laboratory. Results received on 9/8/2023 indicate that the neurotoxin anatoxin-a is present at a level higher than the state level for safe recreational use. The toxin is especially dangerous for small children and animals. Warning signs are posted in the area in which to avoid. 
Preliminary test results from Wade Park in Pasco, Leslie Groves also indicate that anatoxin-a may be present at levels higher than the state level for safe recreational use.

Columbia Point recreational area has been closed pending additional testing following a complaint received by BFHD.

Recreational use of the water at these sites should be avoided until levels drop below recommended guidelines. BFHD continues to take water samples once a week until toxin levels drop back to safe levels. Visitors are cautioned to keep children and pets out of the water until further testing shows the toxins are reduced to safe levels. Sampling at Howard Amon Swim beach will continue weekly until two consecutive samples produce results below the warning threshold. 

Toxic Algae Warning  Lake Closed Sign

No other sites are showing levels of concern. We will continue to keep you updated.

When in Doubt, Stay Out!

Visiting a Lake? Click on the picture to learn the Toxic Algae Status.
Washington State Toxic Algae Map
Toxic Algae Poster
Toxic Algae Poster
(Click photo to download pdf file)