The worrisome algae clumps noted on East and West Twin in recent weeks have been tested and show conclusively that the traces of cyanobacteria in the clumps are well below levels deemed toxic. Cyanobacteria occurs naturally in lakes in Connecticut. It is dangerous only at elevated levels. Officials have given the all-clear on swimming in the lake, for pets and humans. But they generally advise that it still makes sense not to go wading into the clumps as a matter of practice.
The Lakeville Journal reported on the issue last week, and the article offers insights as to the cause of the algae clumps. You can also find more information on cyanobacteria on the DEEP website. Here is a link to the study results, which are also posted on the TLA website.