Dog Owners Warned to Steer Clear of Toxic Algae in Prospect Park View Full Caption

PARK SLOPE — A toxic algae in Prospect Park is putting dog owners on high alert, and some worry their pups have been sickened by the green slime.

Brooklyn dog groups are warning pet owners to steer clear of Prospect Park Lake, where inspectors with the state Department of Environmental Conservation recently confirmed the presence of blue-green algae, which can cause vomiting, diarrhea, rashes and breathing problems in both humans and animals.

Dog walker Johnny Chan of The Prospect Dog said two of his canine clients recently came down with rashes and one of them also developed kidney problems. A vet who treated the animals said he suspected the algae could be to blame, though no tests were conducted, Chan said.

To be on the safe side, Chan won't be letting his clients' pets go swimming anymore this year, and he posted a warning on Facebook alerting others to the mucky menace.

At least one member of FIDO (Fellowship in the Interest of Dogs and their Owners) thinks his dogs got sick after a dip in the lake, said FIDO's Bob Ipcar, and he also wrote an online warning to members.

Blue-green algae, which is technically not algae but "cyanobacteria," sprouts in lakes and streams. Under certain conditions, the pond scum can become toxic. The DEC monitors waterways to see where blue-green algae is blooming. Inspectors also recently spotted it in Central Park Lake, DEC said on its website.

In Prospect Park, only the large lake is listed on the DEC website. It's not clear if the smaller pond, known as "doggie beach," near the Ninth Street entrance, is also affected. A DEC spokesman was not immediately available for comment.

"When enjoying fresh water features in city parks it is important to try to avoid contact with any algae and keep pets on leashes and do not allow them to enter or drink from lakes and ponds unless in areas specifically designated for such activities,” a Parks Department spokeswoman said in an email.