WHITE CITY — The main pond at the Denman Wildlife Area on Thursday became the latest Oregon body of water to host a blue-green algae bloom large enough for authorities to warn people and pets to avoid contact with it.

WHITE CITY — The main pond at the Denman Wildlife Area on Thursday became the latest Oregon body of water to host a blue-green algae bloom large enough for authorities to warn people and pets to avoid contact with it.

The Whetstone Pond, off East Gregory Road, joined Odell Lake in Klamath County and Lemolo Lake in Douglas County as this week's additions to the list of lakes deemed potentially toxic by the state Department of Human Services.

Tests on water from Whetstone sampled July 17 revealed the presence of three forms of the toxic algae, which is technically a bacteria, health reports show.

Though the concentration of each form of algae was lower than the health-hazard threshold of 100,000 cells per milliliter of water, collectively they inched above that figure and triggered Thursday's public-health advisory.

"Even if you're just slipping over the top, it's something you'd like to know," said Clayton Barber, who manages the wildlife area for the Oregon Department of Fish and Wildlife.

Plans are to wait for the algae to dissipate, then take water samples to determine whether algae levels have dropped beneath public-health thresholds, Barber said.

After a two-week wait for any algae-related toxins to dissipate naturally, the advisory will be lifted, according to DHS standards.

The advisory, which is voluntary, will remain in effect indefinitely, Barber said.

Under the advisory, people and pets should avoid all water contact. Anglers are encouraged to practice catch-and-release fishing, and anyone who eats the fish should first remove the skin and fat because toxins can collect there.

Similar advisories were issued Thursday for Lemolo Lake and Wednesday for Odell Lake. The trio remained the only lakes with public-health advisories Thursday.

Lost Creek Lake had a similar algae bloom in June that dissipated just before the July Fourth weekend.

Barber said the bloom was discovered last week while ODFW crews were using water from the 15-acre pond to irrigate a nearby sunflower field on the wildlife area.

"Usually, it's a little turbid, but not this green," Barber said. "No one here had ever seen the water that green here."

Another Denman pond off Agate Road behind the Big R store on Crater Lake Highway had a visible algae bloom Thursday, and tests were pending on that pond as well, Barber said.

Reach reporter Mark Freeman at 776-4470, or e-mail mfreeman@mailtribune.com.