Dogs, beware: Ponds in some of New York City’s most beloved parks are toxic. A state environmental website warns that the green-blue algae blooms discovered in three NYC parks this past month pose a threat to young children and pets. Several dog deaths were also linked to the algae in three other states—Texas, North Carolina, and Georgia—earlier this month. Off limits for New Yorkers are Central Park’s Turtle Pond and Harlem Meer in Central Park, the Morningside Park pond, and the large pond in Brooklyn’s Prospect Park. Prospect Park’s dog beach is still safe for pups wishing to splash and play, and so remains open.

Swimming bans have also been ordered in the Pacific Northwest, Mississippi, and New Jersey earlier this month. Symptoms occur anywhere from 15 minutes to several days after exposure and include diarrhea or vomiting, weakness or staggering, drooling, difficulty breathing and convulsions or seizures, according to CNN.