AVERY COOPER: Toxic algae is once again showing up at a popular park in Richland, Washington. Health leaders are warning people to keep their dogs out of the water. NWPB’s senior environmental correspondent Courtney Flatt has more.

COURTNEY FLATT: The Benton-Franklin Health District has found elevated levels of harmful cyanotoxins at Howard Amon Park in Richland. They started testing water each year when several dogs died in 20-21 after playing in the river.

This particular type of algae grows on rocks at the bottom of the riverbed – with known hotspots about 50 miles up the Columbia River. Jim Coleman is with the health district. He says when the algae gets old, it lifts off the rocks.

JIM COLEMAN: “Sometimes that's exacerbated by extreme heat or if the water drops.” 

FLATT: The algae is buoyant and floats downstream. It often gets caught in a big eddy at the park. Coleman says as long as adults stay away from the mat-like chunks, it should still be OK to recreate in this stretch of the river. 

But, he says, dogs are especially susceptible to the neurotoxin and should stay out of the water.

I’m Courtney Flatt.