Know it, Avoid it, Report it!
Because it is hard to identify an algal bloom as harmful or non-harmful, it is best to avoid swimming, boating, otherwise recreating in, or drinking water with a bloom.
The following information is according to the New York State Department of Environmental Conservation (August 2020).
Most algae are harmless and are an important part of the food web. Certain types of algae can grow quickly and form blooms, which can cover all or portions of a lake. Even large blooms are not necessarily harmful. However some species of algae can produce toxins that can be harmful to people and animals. Blooms of algal species that can produce toxins are referred to as harmful algal blooms (HABs). HABs usually occur in nutrient-rich waters, particularly during hot, calm weather.
Algal blooms may have the appearance of spilled green paint.
People, pets and livestock should avoid contact with any floating mats, scums, or discolored water. Colors can include shades of green, blue-green, yellow, brown or red.
- Never drink, prepare food, cook, or make ice with untreated surface water, whether or not algae blooms are present. In addition to toxins, untreated surface water may contain bacteria, parasites, or viruses that could cause illness if consumed.
- People not on public water supplies should not drink surface water during an algal bloom, even if it is treated, because in-home treatments such as boiling, disinfecting water with chlorine or ultraviolet (UV), and water filtration units do not protect people from HABs toxins.
If contact occurs:
Rinse thoroughly with clean water to remove algae.
- Stop using water and seek medical attention immediately if symptoms such as vomiting, nausea, diarrhea, skin, eye or throat irritation, allergic reactions, or breathing difficulties occur after drinking or having contact with blooms or untreated surface water.
Before you go in the water, find out what waterbodies have blooms or have had them in the past. DEC maintains a HABs Notifications page of waterbodies that currently have blooms. Please note that if a waterbody is not listed, it does not mean that it does not have a bloom. It may have one that was not reported. Find out what waterbodies have had blooms in the past on the HABs Archive page. For additional information, please see the DEC Program Guide (PDF), updated in 2019.
HABs may have the appearance of pea soup.
If you suspect that you have seen a HAB, please report the HAB to DEC.
Fill out and submit a Suspicious Algal Bloom Report Form (leaves DEC website). If possible, attach digital photos (close-up and landscape to show extent and location) of the suspected HAB in the web form. Email HABsInfo@dec.ny.gov if you are not able to complete the form.
Please report any health symptoms to NYS Health Department at firstname.lastname@example.org and your local health department (leaves DEC website)