ST. MARYS — Signs warning swimmers about toxic blue-green algae have been removed from beaches at four state parks, but that doesn’t mean the water is safe.A policy that state officials adopted in June halts testing for algae toxins in lakes after Labor Day weekend, regardless of what might be in the water. Officials also said signs posted at Grand Lake St. Marys, Buckeye Lake, Maumee Bay and Kelleys Island state parks no longer are needed because the state’s traditional swimming season is over.“It is much cooler now. Most people don’t tend to be recreating in the water,” said Laura Jones, an Ohio Department of Natural Resources spokeswoman.At this time last year, there were warnings at seven state parks. The last sign, at Wingfoot Lake State Park in Portage County, was taken down on Dec. 3. That’s after two weeks of tests showed that concentrations of an algae-produced liver toxin in the water were well below a safety threshold set by the World Health Organization.Jack Shaner, a lobbyist with the Ohio Environmental Council, said the state should continue testing and keep warning signs up past Labor Day.”The lifeguard may no longer be on duty, but that doesn’t mean the algae (are) asleep,” he said. ”This is way too early.”Blue-green algae, or cyanobacteria, are common in most Ohio lakes but grow thick in water polluted with phosphorus from manure, fertilizers and sewage that rains wash into streams.Algae liver toxins grew so concentrated at Grand Lake St. Marys last year that the state warned people not to touch the water or take boats out on the lake. Among other things, the state’s new policy allows boating regardless of how much algae is in the water.Chris Abbruzzese, an Ohio Environmental Protection Agency spokesman, said that anyone inclined to visit public beaches now should still be on the lookout for ”any unusual water conditions,” including algae scum, and should avoid swallowing lake water.”The same thing goes for people who have pets,” Abbruzzese said.Milt Miller, co-founder of the Grand Lake St. Marys Restoration Commission, said people are much less likely to be using the 13,000-acre lake’s public beaches now. However, Miller said the lake is still being used by boaters.