COLUMBUS — State officials are warning some people to stay out of Grand Lake St. Marys because of high levels of toxic algae.
"Seniors, children and those with compromised immune systems should stay out of the water," Ohio Department of Natural Resources spokesman Matt Eiselstein wrote in an email statement to the Columbus Dispatch.
The 13,000-acre lake and state park and a local tourism economy that relies on the lake have been plagued with toxic algae problems since high levels were first discovered in 2010. Blue-green algae, also called cyanobacteria, are common in most lakes, but in Grand Lake St. Marys they grow thick feeding on phosphorus from manure that rains washed off nearby farms.
The algae produce liver and nerve toxins that can sicken people and kill pets and fish.
A similar warning was posted last year at this time.