Coffenbury Lake in Fort Stevens State Park is safe for people again, but the water is still dangerous for dogs.
The Oregon Health Authority lifted a health advisory on Wednesday that it had issued in July over blue-green algae and the toxins they produce. Tests showed levels have fallen below state guidelines for human exposure. Toxin levels remain above the very low exposure levels established for dogs, said Rebecca Hillwig, a state natural resource specialist.
The large harmful algae bloom was a first for Coffenbury Lake. Rangers posted signs warning people away from the water and plan to keep a close eye on conditions at the lake in the future, Park Manager Justin Parker said.
This summer, rangers were tipped off that something was wrong when they saw the greenish color of the water and the appearance of a thick scum on the surface of the lake.
“If it’s a gray area, we could close it or not,” Parker said. “We tend to err on the side of public safety.”
The health advisory at Coffenbury Lake didn’t seem to discourage visitors during the park’s busy summer months. People still held picnics and parties and hiked around the lake, Parker said.
“Some folks chose to ignore the ‘avoid contact’ warnings and went in (the water) anyway,” he added.
Only a handful of lakes and waterways across Oregon are monitored for blue-green algae, Hillwig said.
“You’re your own best advocate,” she said, recommending people pay close attention to water they plan to enter or let pets or children play in.
The Oregon Health Authority says people, especially small children and pets, should avoid areas where the water is foamy, scummy or thick like paint, and pea-green, blue-green or brownish-red in color. Sometimes a thick mat of the algae is visible, or bright green cells are suspended in the water column. In such cases, people should avoid any activities in or around the water that could lead to them accidentally inhaling or ingesting droplets.