Swimming is banned at Lake Ronkonkoma Beach for the second time this month, due to high levels of bacteria, the Suffolk County Department of Health announced Sunday.

Levels of cyanobacteria and associated toxins are very high at Lake Ronkonkoma Beach in the Town of Islip and any contact with water should be avoided, according to a county news release.

Bathing in contaminated waters can lead to gastrointestinal illness and numerous kinds of infections, according to Dr. James Tomarken, Suffolk County commissioner of health.

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The beach was last closed July 6 and reopened on July 10.

Lake Ronkonkoma Beach is one of four locations in Suffolk County currently closed due to bacteria: Maratooka Pond in Mattituck, and Agawam Lake and Mill Pond in Southampton are also shuttered.