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More harmful algal blooms found in Helena-area waters

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298663993_428318899314897_5117417661559625764_n.jpg (copy)

This photo is from a harmful algal bloom discovered in August at Hauser Lake.

Lewis and Clark Public Health on Monday said there are still harmful algal blooms being found in the county even as temperatures cool down.

Lake Helena Boat Launch on Lincoln Road, Hauser Lake at York Bridge Boat Launch and Hauser Lake at Clark’s Bay Day Use all contain confirmed harmful algal blooms (HABs), officials posted on Facebook.

All three of these sites measured at 10 ppb microcystins (4 ppb is the EPA caution level where health effects occur). Blooms have been reported earlier in other Helena-area waters, county officials said.

According to the county’s environmental tech, Lake Helena on the south side of the Causeway also looked bad, and probably has the same results as the Lake Helena Boat Launch (although this area was not tested).

When in doubt, stay out, if you suspect an HAB, officials warned. 

Avoid exposure to any water that may contain harmful algae. Be especially vigilant with children, pets and livestock. Direct contact, ingestion or inhalation of cyanotoxins may irritate the skin, eyes, nose and respiratory system or cause nausea, vomiting, diarrhea or headaches.

HABs are caused by blue-green algae that are native to Montana’s freshwater lakes and reservoirs.

Not all varieties are harmful, but some can produce dangerous cyanotoxin. Blue-green algae blooms often look like pea soup, grass clippings or green latex paint, officials said. They are usually suspended in the water or appear as floating mats; they do not grow from the bottom with roots like other water plants.

Children and pets are more likely to ingest HABs because they spend most of their time wading in the shallow waters where algae can accumulate, and they have less control over how much water they ingest.

Officials said those who catch fish in waters where blooms have been reported should discard all of the fish's organs and clean it well. They also cautioned people not to touch the water.

If you suspect an HAB-related illness in a person or animal, call Poison Control at 1-800-222-1222 and seek medical attention.

For more information visit

Report a suspected HAB at or call 1-888-849-2938. You may also report a suspected HAB by calling Lewis and Clark Public Health, Environmental Health Division, at 406-447-8351.


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