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Energy and Environment Cabinet

Division of Water
Harmful Algal Blooms

​Blue-green algae occur naturally in the environment and are a vital part of the ecosystem. Harmful algal blooms arise when there are excess nutrients (phosphorus and nitrogen), sunny conditions, warm temperatures and low-flow or low-water conditions. The more typical green algae, which do not produce toxins, come in many forms and may appear as underwater moss or stringy mats.

Blue-green algae, on the other hand, appear as slicks of opaque, bright-green paint, but closer inspection often reveals the grainy, sawdust-like appearance of individual colonies or bacteria. The color of the algae may also appear red or brown.


HAB Advisories:
  • The are no advisories at this time
    Click here to access the HAB map viewer.  HAB warnings are identified on the map viewer by a Red diamond and HAB watches are identifed by a Orange diamond. (Note:  this viewer will only work when using one of these web browsers: Google Chrome, Firefox or Safari.)

    Public lakes or rivers identified with a HAB advisory remain open to the public.

    To report a HAB please contact the KY Division of Water at 502-564-3410.

Recommended Precautions:

The following guidelines are recommended to avoid exposure to HABs:

  • Individuals should avoid direct contact with affected water that has unusual color or where blue-green algae have been identified, including swimming, wading, paddling, diving, and water skiing.
  • People who are prone to respiratory allergies or asthma should avoid areas with HABs. Children may be particularly sensitive.
  • If you come into contact with water containing blue-green algae, wash off with clean, fresh water. In some cases, skin irritation will appear after prolonged exposure. If symptoms persist, consult your local health care provider.
  • Fish fillets (not organs) may be consumed after the fillets have been rinsed in clean, non-lake water.
  • Prevent pets and livestock from coming into contact with water where HABs are apparent.

If you are concerned that you have symptoms that are a result of exposure to HABs please see your doctor and call your local health department.

Additional Information:

HABs can develop over a short period of time. Visitors are still advised to be aware of the potential for a harmful algal bloom and follow the recommended precautions.

To read more about HABs, click on the links below:

Harmful Algal Bloom Photos