TOLEDO, Ohio (AP) – The U.S. Environmental Protection Agency says it shouldn’t have approved Ohio’s recommendation not to declare Ohio’s western end of Lake Erie impaired by toxic algae.

The agency’s reversal didn’t go as far as ordering the lake to be designated as an impaired watershed. But the EPA’s reversal sent in a letter to Ohio officials last week said the state’s list of impaired waters was incomplete and didn’t properly evaluate the lake’s waters.

Several environmental groups have sued EPA saying the lake should be classified impaired because algae blooms are preventing the waters from meeting basic quality standards.

The designation would pave the way for increased pollution regulations in the shallowest of the Great Lakes. Algae outbreaks have fouled drinking water in recent years and are a threat to wildlife.