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MDHHS, MDARD, EGLE and local health departments provide tips on how to stay safe from Harmful Algal Blooms

Michigan residents living near or visiting bodies of water should be aware of the potential for harmful algal blooms (HABs). The Michigan Departments of Health and Human Services (MDHHS); Environment, Great Lakes, and Energy (EGLE); and Agriculture and Rural Development (MDARD) have collaborated with Michigan’s local health departments (LHDs) and expanded HAB testing efforts to increase public safety around HABs.

HABs form due to a rapid growth or “bloom” of cyanobacteria. Cyanobacteria naturally occur in lakes, rivers and ponds; however, they can produce toxins, called cyanotoxins, that can be harmful to people and animals. In 2022, HABs were reported in 80 water bodies in 38 Michigan counties. Breathing in or swallowing water with HAB toxins may cause illness, such as runny eyes or nose, asthma-like symptoms, difficulty breathing, stomach pain, vomiting, diarrhea, weakness, headaches or dizziness. Skin contact may cause rashes, blisters or hives.

“If you had contact with or swallowed water with a suspected HAB and feel sick, call your health care provider or seek medical attention as soon as possible,” said Dr. Natasha Bagdasarian, MDHHS chief medical executive. “If you have questions about algal blooms and keeping yourself safe, call 800-648-6942.”

HAB reports are increasing in frequency and geographic distribution across Michigan. To increase HAB response capacity, MDHHS starting funding LHDs to do their own site visits and testing for HABs in 2022. Participating LHDs visit suspected HAB sites, collect samples, test them for cyanotoxins and send data and samples to MDHHS. LHD testing for HABs has provided additional capacity to respond to the increasing number of HAB reports.

The following LHDs are participating in the MDHHS HABs testing project:

  • Allegan County Health Department (2022 and 2023).
  • Barry-Eaton District Health Department (2022 and 2023).
  • District Health Department #2 (Alcona, Iosco, Ogemaw and Oscoda counties) (2022 and 2023).
  • District Health Department #10 (Crawford, Kalkaska, Lake, Manistee, Mason, Mecosta, Missaukee, Newaygo, Oceana and Wexford counties) (2022 and 2023).
  • Kalamazoo County Health Department (2023).
  • Livingston County Health Department (2022 and 2023).
  • Mid-Michigan District Health Department (Clinton, Gratiot and Montcalm counties) (2022 and 2023).
  • Monroe County Health Department (2022 and 2023).
  • Public Health Muskegon County (2022 and 2023).
  • Washtenaw County Health Department (2022 and 2023).
  • Western Upper Peninsula Health Department (Baraga, Gogebic, Houghton, Keweenaw and Ontonagon counties) (2022 and 2023).

HABs are often green but can be other colors and can be different textures, such as spilled paint, scums, streaks, mats or discoloration of the water with algae. They typically occur May to October, and most often in August and September.

What should people do if they think they have found a HAB?

  • Do not let people, pets or livestock in the water or near the shore in affected areas.
    • You can use unaffected areas of a lake unless a bloom covers most of the lake.
  • Always rinse off people and pets after contact with any lake water.
  • If there is a posted HAB advisory or closing, follow its instructions.
  • Report suspected HABs to EGLE by e-mailing with pictures of the suspected HAB. Residents can also call 800-662-9278 to report.
  • If you had contact with or swallowed water with a suspected HAB and feel sick, call your doctor or Poison Control at 800-222-1222. If symptoms are severe, get medical attention right away.
  • Report HAB-related illnesses to your local health department.

What are the threats of HABs to animal health?

Animals, including dogs, can have vomiting, diarrhea, staggering, seizures or even die after contact with HABs. To prevent illness, keep dogs away from discolored or scummy water and shorelines, rinse them off after contact with lake water and bring them clean drinking water. If an animal gets sick after contact with a HAB, call a veterinarian right away. Report animal illness due to HABs to MDARD via this form or phone at 800-292-3939.

Contacts for HAB questions

  • Visit for more information on HABs.
  • For more information on HABs and your health, call MDHHS at 800-648-6942.
  • For more information on HABs and pets or livestock, call MDARD at 800-292-3939.
  • For more information on HABs and the environment, call EGLE at 800-662-9278.



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