GARRARD COUNTY, Ky. (WKYT) -People who are planning to swim or boat in one central Kentucky lake are being told to be aware of a harmful substance.

Kentucky environmental leaders say there is a “harmful algal bloom” or HAB on Herrington Lake.

“If it gets into the drinking water for people, it’s harmful, if not deadly, if you consume enough of it.”

People have noticed the surface of the lake has taken on a different color over the past few weeks.

“It blocks sunlight, it absorbs oxygen when it dries out. It can kill mass groups of fish,” said Jonathan Tyler, who works on boats for Outboard Connection in Nicholasville but says he’s on the lake several times a week, sometimes every day. He’s seen the algae increase.

“If it gets into the drinking water for people, it’s harmful, if not deadly, if you consume enough of it.”

State leaders say the drinking water supply is not impacted at this time, but the Kentucky Division of Water is closely assessing the situation and will provide updates.

Tyler says he’s only seen it in a handful of locations.

“Of course, if you’re skiing, tubing, or boarding and you run through a plume of it, you’re going to be ok. But I think it’s more of a concern with Herrington with the fish population,” he said.

People are not being told to avoid the water, just to pay attention.

“If you see the color of the water change to a light green, and it looks cloudy, I would definitely try to avoid those areas,” Tyler said.

As of now, the algae have been confirmed at Paradise Camp and Tanyard Branch or Redgate.

Copyright 2025 WKYT. All rights reserved.