OAKLAND, Calif. (KTVU) - On a typical summer day, Lake Temescal beach would be blanket to blanket with people - but not these days.
On Thursday there was just a handful of folks, and some disappointment.
"It probably would have been a lot more fun to play around in the water, but we're just going with the flow," said Megan Mischke, who was sprawled out on a blanket with her two-year-old daughter.
The East Bay Regional Park District has closed the lake because of a bloom of blue-green algae. It's toxic, and there's five times the maximum safety limit of it in the lake.
"If you swallow any water, this toxin can attack the liver. That's the primary concern," says Hal Maclean of the park district.
The same bloom was also found in Lake Chabot in Castro Valley and Quarry Lakes in Fremont.
It also appeared last year and forced Lake Temescal to close for two months.
But the East Bay Regional Park district says it is still rare, and it is probably due in part to the lack of rain.
"By having low water levels and the drought, a warm winter, the algae hasn't had a winter to get knocked down," said Maclean.
The toxic bloom has all but killed off the park district's Junior Lifeguard program, as there is no water rescue training until the water is safe again.
The plan is to treat the lake with a chemical to kill the algae. That's set to happen next week.
The park district says i will keep monitoring the toxic levels. But it isn't offering up any predictions on when Lake Temescal will be safe for swimming.