Healthy Gallatin warns algae blooms can kill dogs
By Moosetrack Megan

Posted: August 14, 2019

In the past few weeks dogs in Texas, Georgia, Pennsylvania, North Carolina, and New Jersey have all died after recreating in lakes with algae blooms, prompting Montana authorities to also release information about the blooms.


From Healthy Gallatin 

As Montanans and visitors head to the lake for late summer fun, public health officials urge citizens to
know the health risks of Harmful Agal Blooms, or “HABs”.

HABs are caused by blue-green algae that are native to Montana’s freshwater lakes and reservoirs. Not
all varieties of blue-green algae are harmful, but some can produce dangerous cyanotoxins. Blue-green
algae blooms often look like pea soup, grass clippings or green latex paint. The algae are usually
suspended in the water or appear as floating mats; they do not grow from the bottom like roots,
mosses, or water plants.

Scientists believe that blooms are occurring at more locations, with increased frequency and for a longer
time. Potential causes include warmer water temperatures, longer summer growing seasons and
increased nitrogen and phosphorous runoff from a variety of human activities. Under certain conditions
HABs can produce toxins that damage the skin, liver and nerve cells. These toxins can make people and
animals sick, and at worse, exposure can be fatal.

Importantly, “children and pets are more likely to ingest HAB infested waters 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”, said Matt Fergusun, State Toxicologist.

Hannah Riedl, water quality specialist at DEQ said, “ because we can’t track rapidly changing conditions
in every body of water, we want people to be informed enough to make their own decisions. We also
ask the public to help by reporting HABs so that we can respond quickly and hopefuly prevent people,
pets and livestock from getting sick.”

Suspected HABs can be submitted, including photos, to the website: This site also has
a live map of reported HABs and identification information. When a HAB is reported to either DEQ or
directly to the Gallatin City-County Health Department it is investigated to determine whether the
bloom is nuisance green algae or potentially-toxic blue-green algae. In Gallatin County, the health
department then works with the entities managing the waterbody to determine whether water quality
testing results warrant safety advisories.

The City of Bozeman Water Treatment Plant personnel collect and test water samples weekly from
multiple locations in Hyalite Reservoir for the presence of microcystin. This testing is done from July to
October. The City of Bozeman monitors Mystic Lake for signs of HABs as well throughout the summer.
Suspect a HAB? “When in doubt, stay out. Do not drink, swallow, or swim in water that shows signs of a
HAB and be sure to keep kids, pets, and livestock out too” said Matt Kelley, Health Officer for Gallatin
City-County Health Department. Direct contact, ingestion or inhalation of cyanotoxins may irritate the
skin, eyes, nose and respiratory system or cause nausea, vomiting, diarrhea or headaches. If you suspect
a HAB-related illness in a person or animal call Poison Control 1-800-222-1222 and seek medical

Report a suspected HAB at or call 1-888-849-2938. You may also report a suspected
HAB by calling the Gallatin City-County Health Department Environmental Health at 406-582-3120.