The web Browser you are currently using is unsupported, and some features of this site may not work as intended. Please update to a modern browser such as Chrome, Firefox or Edge to experience all features Michigan.gov has to offer.
Harmful Algal Blooms
Harmful Algal Blooms
Michigan's Department of Environment, Great Lakes, and Energy (EGLE) staff discover or receive reports from lake associations, and the broader public each year about nuisance algal conditions. The number of such reports, particularly the occurrence of cyanobacteria or blue-green algae blooms and concern over the possible presence of algal toxins such as microcystin, appear to have increased in recent years. In particular, severe blooms were observed in the western basin of Lake Erie in August 2014, and access to drinking water for hundreds of thousands of people was temporarily interrupted due to elevated levels of an algal toxin associated with the bloom. This event caused EGLE to re-examine and expedite our efforts related to blue-green algae blooms, including what constitutes a harmful algal bloom (HAB); our monitoring approach; sampling protocols; analytical capabilities and costs; information gaps; and communication with other agencies, stakeholders, and the public on this issue.
Summer is peak season for the formation of harmful algal blooms (HABs) that can present health hazards to people and pets. In Michigan, algal blooms typically occur during periods of warm temperatures, lots of sun, and high nutrient levels.
It is not possible to determine whether algal blooms contain harmful toxins by looking at them, so it is best to avoid contact with any body of water that is covered with algal mats or significant rafts of algae on the surface.
EGLE and the Michigan Department of Health and Human Services (MDHHS) sample for HABs on a limited basis and work with local health departments to protect the public when toxins are discovered; however, some areas affected by HABs may go undetected. Suspicious-looking algae can be reported to EGLE by calling the Environmental Assistance Center at 1-800-662-9278 or sending an e-mail to AlgaeBloom@Michigan.gov.
Michigan harmful algal bloom reports web map
This map shows locations of bloom reports that have been verified by EGLE and results of any cyanotoxin tests conducted by EGLE, MDHHS, and partner agencies.
Note that not all HABs in Michigan are reported to EGLE and so may not be included on the map. HABs can move around, disappear and reappear – meaning that HABs may be present in waterbodies, but not present on the map. Before going in any water, MDHHS recommends that you always look for and keep away from visible HABs or scums and that people and pets stay out of water in affected areas.
Harmful algal blooms story map
This story map covers all that and more including how to prevent and report blooms if you suspect there may be one on a waterbody in Michigan.
- Michigan Harmful Algal Bloom Reports map
- HAB Picture Guide
- Webinar: Harmful Algal Blooms in Michigan’s Recreational Waters, July 13, 2023
- EGLE Classroom - Identifying Harmful Algal Blooms (Cyanobacteria) video
- Frequently Asked Questions (FAQ's)
- Michigan HAB FAQ sheet
- HAB Veterinarian's Handout
- HAB Animal Owner's Handout
- Ohio EPA HAB Visual ID
- Kentucky Algae ID Guide
- 2021-2022 Cyanobacteria Bloom Monitoring
- 2022 HAB Monitoring QAPP
- 2020 HAB Monitoring QAPP
- 2016 - 2019 HABS Lake Sampling Results
- 2020 Canine Death Report
- 2016 - 2018 Inland Lake Monitoring Results Report
- 2019 HAB Monitoring QAPP
- 2018 HAB Monitoring Map
- 2017 Algal Toxin Monitoring Report
- 2016 Algal Toxin Monitoring Results for Michigan Inland Lakes
- 2017 HAB Monitoring QAPP
- EGLE Harmful Algal Bloom Grant Awards
- Harmful Algae Bloom Summary Document
- 2017 Algal Bloom Tracking Report
- 2016 Algal Bloom Tracking Report
- 2015 Algal Bloom Tracking Report
- 2015 HAB Monitoring Results Report
- Drinking Water Impacts in Michigan
- 2016 Monitoring Plan
- 2015 and 2016 Algal Toxin Monitoring Locations