Scooteney Reservoir has been closed to swimmers because of a toxic algae bloom especially dangerous to small children and animals was found.
The Benton-Franklin Health District ordered the lake closure on Monday after test results from Friday showed toxic levels of a form of algae called Microcystis aeruginosa.
Environmental health staff first noticed an algae bloom Aug. 17 at the reservoir 36 miles north of Pasco.
People and animals could get sick if they swallow the water. Symptoms include jaundice, shock, abdominal pain, nausea/vomiting, severe thirst, rapid pulse and death, and could take 30 minutes to a day to appear depending on the amount ingested and size of the person or animal, said the health district.
Benton-Franklin health officials caution visitors to make sure children and pets stay out of the water until tests show reduced toxin levels. The toxin can remain in the water for a week after the algae bloom disappears.