Coast Guard officials have warned that a nearly 10-mile stretch of red tide has been spotted in New York Harbor. The algal bloom can be a natural seasonal occurrence, and generally happens when the seas are warm. The toxin-producing phenomena can cause temporary breathing problems, burning eyes and skin irritation, according to the AP. It's also detrimental to the shellfish industry, making it unsafe to eat, and often kills fish.

Swimmers and boaters are being warned to avoid the water, which is reddish-brown and was seen near the Intrepid Sea, Air & Space Museum, as well as off Staten Island and Jones Beach.

According to the Coast Guard, it will eventually disperse and drift out to sea, but spokesman Charles W. Rowe says until then, “stay away from it and anything in it."