HAB DANGERS AND COSTS
Harmful Algal Bloom Dangers, Health Risks and Costs
From the Great Lakes to backyard ponds, harmful algae blooms caused by toxic cyanobacteria are spreading through freshwater in all 50 states. These toxins are in the water your family swims in, the water your dog drinks from, and increasingly, the water that comes out of your tap.
This page covers what the danger actually is, what blooms have cost communities in real dollars, and why the same water blooms again the following year. Every figure below is sourced, and the full source list is at the bottom of the page.
134,000
U.S. lakes with microcystin detected, half of all lakes in EPA's national survey
$1.1 billion
spent by U.S. communities on harmful algal blooms since 2010
400,000
Toledo residents who could not drink their tap water in 2014
80+
known cyanotoxins produced by cyanobacteria
Sources: EPA, National Lakes Assessment 2022; EWG, The High Cost of Algae Blooms; Statehouse News Bureau; EPA, Common Cyanotoxins
Sources kept by Hydralife Solutions. Last updated October 2026.
QUICK ANSWER
What is a harmful algal bloom?
A harmful algal bloom (HAB) is a dense overgrowth of cyanobacteria, the organisms most people call toxic algae, fed by excess nitrogen and phosphorus in the water. Many blooms produce cyanotoxins that attack the liver, brain, lungs and skin. People can be poisoned by drinking the water, swimming in it or breathing near it, dogs can die within hours, and the toxins cannot be boiled out, filtered with a household pitcher filter or destroyed with chlorine.
THE CAUSE
Cyanobacteria, excess nutrients and why blooms keep growing
What most people call toxic algae is actually cyanobacteria, an ancient microorganism that photosynthesizes like microalgae but is built differently. Cyanobacteria have no cell nucleus and none of the other membrane-bound structures that a true alga carries. That makes cyanobacteria a fundamentally different organism from the beneficial algae and phytoplankton that keep water healthy. When excess nutrients wash into a lake, pond or stream, they feed these cyanobacteria, and the cyanobacteria explode into thick, dangerous blooms that produce cyanotoxins and poison the water.
EPA's 2022 National Lakes Assessment rated 50 percent of U.S. lakes in poor condition for phosphorus and 47 percent in poor condition for nitrogen, making nutrient pollution the most widespread stressor it measured. That is roughly 134,000 lakes primed for cyanobacteria blooms right now. Not all algae are bad: many species of algae and phytoplankton are essential to healthy aquatic ecosystems. The problem is specifically cyanobacteria, and the excess nutrients that feed them.
Source: EPA, National Lakes Assessment 2022 Key Findings
Where do these excess nutrients come from?
Nitrogen and phosphorus enter waterways from agricultural runoff, lawn care products, stormwater drains, aging sewer systems and industrial discharge. American agriculture applies roughly 12 million tons of nitrogen and 4 million tons of phosphate each year, and crops do not absorb all of it. Rain washes the excess into nearby lakes, ponds and streams, where it breaks down into the dissolved ammonia, nitrite, nitrate and phosphate that cyanobacteria feed on. Those same four nutrients are exactly what beneficial phytoplankton consumes, which turns a pollution problem into a recoverable resource.
Sources: EPA, Sources and Solutions: Agriculture; USDA Economic Research Service, Fertilizer Use and Price
Why harmful algae blooms are getting worse every year
Warmer temperatures make cyanobacteria grow faster and bloom earlier. In western Lake Erie, research covering 1995 to 2022 found the bloom season expanding by up to a month and potential cyanobacterial growth rates rising by as much as 30 percent, with the effect strongest in warm, shallow water. NOAA detected cyanotoxins in Lake Erie on April 28, 2025, earlier in the year than in any season on record, and the 2022 bloom ran into November.
Source: Gregory J. Dick, University of Michigan Cooperative Institute for Great Lakes Research, Toxic algae blooms are lasting longer in Lake Erie, June 2025
THE SCALE
Harmful algal blooms are spreading faster than ever
Thirty years ago harmful algae blooms were rare. Today cyanobacteria have been found in freshwater lakes, ponds and streams in every state, and EPA's 2022 National Lakes Assessment detected microcystins in 50 percent of lakes nationally, up from 21 percent just five years earlier. Those are only the lakes being sampled. The millions of small ponds on farms, in neighborhoods and at parks are not tested at all.
50%
of U.S. lakes with microcystins detected in 2022
21%
five years earlier, in 2017
268,020
lakes represented by EPA's survey, every water body of at least one hectare and one meter deep
3.5 million
ponds on farms and in communities, almost none of them tested
Source: EPA, National Lakes Assessment 2022 Key Findings
Where blooms are being reported this season
Hydralife tracks reported freshwater blooms across the country on a live national map. See this season's reported blooms on the HAB Map 2026
HAB hotspots in every U.S. region
Harmful algae blooms are not limited to a few problem areas. Every region of the United States is affected.
OH, MI, MN, WI, IN, IL
Great Lakes and Midwest
Lake Erie has had annual toxic cyanobacteria blooms since 2002, and the 2024 bloom began June 24, the earliest ever recorded. Inland lakes across Minnesota, Wisconsin, Indiana and Illinois are seeing rapidly increasing HAB events fueled by excess phosphorus and nitrogen.
FL, GA, AL, SC, NC
Southeast
Florida's Lake Okeechobee has been besieged by cyanobacteria for decades, producing blooms that contaminate downstream waterways. HABs are spreading across freshwater bodies throughout the Southeast as temperatures rise.
NY, PA, VT, NH, MA, CT
Northeast
HABs increasingly affect lakes and reservoirs across New England and the Mid-Atlantic. Lake Champlain, the Finger Lakes and countless smaller ponds and reservoirs are seeing more frequent and more severe cyanobacteria blooms each year.
OR, WA, ID
Pacific Northwest
Salem's 2018 drinking water crisis showed how vulnerable the region is. HABs are increasing across Oregon, Washington and Idaho, and Oregon had no dedicated HAB funding until recently.
UT, CO, CA, NV, MT
West and Mountain States
Utah Lake has carried a warning advisory with microcystin, anatoxin and cylindrospermopsin all detected at once. California's Clear Lake, Colorado reservoirs and mountain lakes across the Rockies are all seeing growing HAB problems driven by warming temperatures and nutrient pollution.
TX, OK, KS, MO, AR, LA
South and Central
Warm climates and agricultural activity make this region highly vulnerable. Texas lakes, Kansas reservoirs and farm ponds across the Great Plains are seeing cyanobacteria blooms start earlier and last longer each year.
Sources: NOAA, Lake Erie HAB Forecasts; EPA, Agriculture Nutrient Pollution; University of Michigan, Lake Erie HABs
HEALTH RISKS
Cyanotoxins: how harmful algal blooms harm people
Cyanobacteria produce over 80 known cyanotoxins, and they attack the liver, brain, kidneys and skin. Some are linked to cancer, and others are under investigation for links to neurological disease. You can be poisoned by drinking the water, by swimming in it, or by breathing near it. Swallowing the water carries the highest risk, but you do not have to touch the water to be exposed at all.
Liver damage from microcystin
The most common cyanotoxin, microcystin, attacks the liver, and long-term exposure is linked to liver cancer. Microcystin is now found in half the lakes EPA samples nationally.
Brain and nerve damage from anatoxin-a, saxitoxin and BMAA
Anatoxin-a and saxitoxin act on the nervous system. Exposure can bring on tingling, numbness, muscle twitching, dizziness and, at high doses, paralysis and respiratory failure, which is why anatoxin is so often behind rapid dog deaths at the water's edge. A third compound, BMAA, is produced by many cyanobacteria and is under investigation for a possible link to ALS and other neurodegenerative disease; that link is not yet settled science.
Breathing problems from airborne cyanotoxins
Cyanotoxins can become aerosolized, turning into microscopic airborne particles. Wind, waves and boat traffic lift them off the surface of contaminated lakes and ponds, and researchers have detected cyanotoxins on air filters worn by people simply walking near affected water. Families living near freshwater with harmful algae blooms report sore throats, coughing, asthma-like reactions and chronic respiratory irritation without ever going in the water. State health agencies now advise avoiding activities that aerosolize bloom water, naming water skiing and power boating specifically.
Skin and eye irritation from contact
Touching water contaminated with cyanobacteria causes rashes, hives and painful skin irritation. Eye irritation and stomach illness are common after swimming in freshwater lakes and ponds with active harmful algae blooms.
You cannot boil cyanotoxins out, filter them with a household pitcher filter, or destroy them with chlorine. If you or someone close to you is ever exposed, knowing that the cause is cyanobacteria, and saying so, can get you the right medical attention faster.
Sources: EPA, Common Cyanotoxins; CDC, Clinical Signs and Symptoms; CDC, Harmful Algal Blooms and Your Health; NIEHS, Algal Blooms; Oregon Health Authority, Cyanobacteria Blooms FAQ; PMC, Aerosolized Cyanobacteria in the Human Respiratory Tract; Environmental Science and Technology, Toxic Cyanobacteria
DRINKING WATER
When a bloom shuts off a city's water supply
A harmful algal bloom in a source lake can push cyanotoxins through a treatment plant and into the tap. Toledo and Salem both learned this the hard way.
TOLEDO, OHIO. AUGUST 2014
Toledo: 400,000 people told not to drink, cook with or boil their water
400,000
people told not to drink, cook with or boil their tap water
About 2.5 days
until the do-not-drink advisory was lifted
$401.7 million
invested since in stormwater, wastewater and drinking water treatment
At 2 a.m. on August 2, 2014, a harmful algae bloom in Lake Erie pushed microcystin through Toledo's treatment plant and the city issued a do-not-drink advisory. As many as 400,000 people could not drink their tap water, cook with it, or boil it. The governor declared a state of emergency. The advisory was lifted on the evening of August 4, roughly two and a half days later. Toledo has since invested $401.7 million in stormwater, wastewater and drinking water treatment infrastructure, and many residents still hesitate over their tap water a decade later.
SALEM, OREGON. MAY 2018
Salem: a month-long contamination event in the state capital
Cyanotoxins from a harmful algae bloom in Detroit Lake passed through Salem's filtration plant and into tap water, triggering a month-long contamination event. Bottled water sold out within hours. The governor declared a state of emergency and the National Guard distributed water to residents.
Why boiling water makes cyanotoxins worse
During the Toledo emergency, residents were told specifically not to boil the water. Boiling does not destroy cyanotoxins, and it ruptures the cyanobacteria cells themselves, releasing the toxin that was held inside them. Oregon Health Authority puts it plainly: boiling splits the cells open and makes the problem worse. The same principle explains why killing a bloom does not end it. Whether the cells are ruptured by heat or by copper, what was inside them ends up in the water.
Sources: Statehouse News Bureau; Oregon Public Broadcasting; Oregon Health Authority
PETS
Why harmful algal blooms are dangerous for dogs, often within hours
Dogs are the most frequent victims of cyanobacteria, because they drink from and play in freshwater ponds, lakes and puddles. Cyanotoxins are just as deadly in a small community pond as in a Great Lake. A dog can absorb a lethal dose without showing any warning sign until it is too late, and there is no antidote for cyanotoxin poisoning.
How dogs are exposed, and what to watch for
Dogs are poisoned by drinking contaminated water, by swallowing bloom material while swimming, or by licking toxic residue off their fur after getting out. Symptoms can appear in as little as one to three and a half hours and progress rapidly to seizures, collapse and death. Watch for vomiting, diarrhea, staggering, lethargy, seizures and sudden collapse. By the time symptoms appear it is often too late for treatment.
Documented dog deaths from harmful algal blooms
Lake Travis, Texas, 2021
Two dogs died and five were sickened by cyanotoxin exposure at a popular swimming area.
Michigan, 2019
Four dogs died after exposure to cyanobacteria in a private pond.
Kansas, 2011
Five confirmed dog deaths from HAB-associated cyanotoxin poisoning.
A national tracking map has recorded at least 32 animal deaths since 2010, and researchers say the true number is far higher because most cases are never reported.
Sources: Cornell Veterinary Medicine; EWG, Dog Deaths Linked to HABs; PMC, Canine Dihydroanatoxin-a Mortality
WILDLIFE AND FISH
Fish kills, wildlife deaths and dead zones
Harmful algae blooms devastate whole aquatic ecosystems. In everything from Great Lakes to backyard ponds, dense cyanobacteria blooms block sunlight, deplete oxygen and create dead zones where fish and other aquatic life suffocate. When fish start dying, it is often the first visible sign that a water body is in serious trouble.
391,516
fish deaths documented in Maryland in 2022 alone
Massive fish kills, most of them never counted
Fish kills in small ponds, community lakes and farm stock tanks happen constantly without ever being counted. A single bloom in a two-acre pond can kill everything in it overnight and turn a community asset into a health hazard.
Birds, mammals and livestock
Cyanotoxins move through the food chain in ponds and lakes of all sizes. Birds, mammals and livestock that drink from contaminated water are at risk, and small, unmonitored water bodies are the most dangerous, because nobody is testing them.
Eutrophication, hypoxia and dead zones: how a bloom suffocates a pond
STEP 1
Nutrients build up
Eutrophication is the enrichment of a water body with nitrogen and phosphorus. It is the condition that makes a harmful algae bloom possible, not the damage the bloom does.
STEP 2
The bloom takes over
A dense bloom shades out everything below it, and at night the bloom itself respires and draws down dissolved oxygen.
STEP 3
The bloom collapses
When the bloom collapses, bacteria decompose the dead cells and consume what oxygen is left.
STEP 4
A dead zone forms
Dissolved oxygen falls to hypoxic levels, then to anoxic ones, and the area becomes a dead zone where fish, insects and other aquatic life suffocate.
In a deep lake this plays out over weeks. In a shallow pond it can happen between sunset and sunrise, which is why pond owners so often find a complete fish kill in the morning after seeing nothing wrong the day before. Ending a bloom by force does not avoid this: a bloom that is killed decomposes exactly the way a bloom that dies on its own does, and it releases its stored cyanotoxins while it goes. Drawing the nutrients down before the bloom forms is what keeps the oxygen in the water.
Sources: WHOI, Fish Kills; Maryland DEQ, 2022 Fish Kill Summary
SMALL PONDS
Small ponds and harmful algae blooms: your pond is at risk too
The headlines focus on Lake Erie and Lake Okeechobee, but toxic cyanobacteria are quietly choking thousands of community ponds, farm ponds, small lakes and local swimming spots across the country. There are over 3.5 million ponds on farms and in communities in the United States, and the vast majority are never tested. These smaller waters are often hit hardest, because they get no monitoring, no funding and no attention.
COMMUNITIES
Community and HOA ponds
Stormwater retention ponds and decorative community lakes are prime targets, because they collect phosphorus and nitrogen from lawns, parking lots and storm drains. When blooms appear, children and pets are at immediate risk, and HOAs face stormwater compliance fines of up to $70,000 per month. Many communities resort to expensive, short-lived chemical treatments that only bring the problem back stronger.
AGRICULTURE
Farm ponds and irrigation water
With over 2.5 million farm ponds nationwide, agricultural ponds are ground zero for harmful algae blooms. They collect excess phosphorus and nitrogen from fields, nutrients that feed cyanobacteria instead of crops, and blooms clog irrigation equipment and poison livestock water.
RECREATION
Local fishing spots, swimming holes and beaches
Small lakes, creeks and swimming areas that families have used for generations are being shut down by harmful algae blooms. State parks, county recreation areas and scenic swimming spots are being closed or posted with health warnings at record rates, while countless small lakes and ponds at campgrounds, RV parks and neighborhood swim areas are never tested at all, which leaves visitors unaware they are being exposed. A single bloom can leave a small pond unsafe for months.
GOLF
Golf course ponds
Nearly 16,000 U.S. golf courses rely on ponds for irrigation and for appearance. Cyanobacteria-choked ponds damage turf quality, clog spray heads and create odors, and courses spend thousands annually on chemical treatments that give only temporary relief.
Sources: Maryland DEQ, 2022 Fish Kill Summary; WHOI, Fish Kills from Freshwater HABs; Environment America, 2024 Beach Report
THE COST
What harmful algal blooms cost communities, utilities and property owners
Harmful algae blooms are not only a health crisis. They are an economic one. Homeowners watch property values fall, cities spend hundreds of millions upgrading treatment to handle cyanotoxins, and tourism businesses lose entire seasons. Since 2010, U.S. communities have spent more than $1.1 billion on harmful algae bloom treatment, prevention and remediation, documented across 85 locations in 22 states, and it gets more expensive every year.
$1.1 billion
spent by U.S. communities on HABs since 2010
85
locations documented
22
states
$82 million
a year in national losses from closed beaches, closed shellfish beds and reduced fishing
Property values crushed by blooms
1.7%
drop in nearby property value for every 1 microgram per liter increase
11 to 30%
value lost by homes directly on affected lakes
$152 million
lost by homeowners at Buckeye Lake and Grand Lake St. Marys
Ohio State University research found that for every one microgram per liter increase in bloom concentration, nearby property values drop 1.7 percent, about $2,205 per home. Homes directly on affected lakes lose 11 to 30 percent of their value. At Buckeye Lake and Grand Lake St. Marys alone, homeowners lost a combined $152 million.
Water treatment costs are rising
$289 million
spent by 12 major U.S. cities upgrading treatment for cyanotoxins
34%
jump in Clear Lake, California treatment costs during bloom season
$815 million
spent in Ohio, 70 percent of documented HAB remediation nationwide
Twelve major U.S. cities have spent $289 million upgrading water treatment to handle cyanotoxins. Clear Lake, California saw treatment costs jump 34 percent during bloom season, with residents paying double the affordability threshold for water. Ohio communities alone account for $815 million, 70 percent of all documented HAB remediation spending nationwide.
Tourism and recreation losses
453 beaches
potentially unsafe on at least 25 percent of tested days in 2024
1,027 days
of beach closures or advisories in Ohio in a single year
29%
of Lake Erie fishing trips canceled when blooms are present
More than 453 beaches were potentially unsafe for swimming on at least 25 percent of tested days in 2024, and Ohio alone recorded 1,027 beach closure or advisory days in a single year. When Lake Erie blooms are present, up to 29 percent of fishing trips are canceled, costing Michigan $5.9 million a year in lost angling revenue. NOAA estimates that harmful algal blooms cost the U.S. economy at least $82 million a year in closed beaches, closed shellfish beds and reduced fishing, and puts the 2011 Lake Erie bloom alone at nearly $71 million in lost economic benefit.
Sources: EWG, The High Cost of Algae Blooms; Ecological Economics, Bloom and Bust; Grist; Environment America, 2024 Beach Report; NOAA, The Untold Story of HABs
THE SPENDING GAP
Billions spent, and harmful algal blooms are still spreading
The federal government has spent hundreds of millions studying harmful algae blooms and cyanobacteria, and states have spent hundreds of millions more managing them. The problem is still growing, because most of that investment has gone into monitoring and understanding blooms rather than removing the nutrients that cause them.
FEDERAL
Federal HAB research spending
$101 to $110 million
spent by 12 federal agencies in fiscal years 2013 to 2015
$168 million
spent by NOAA alone, 2013 to 2021
A 2017 GAO audit found that 12 federal agencies spent $101 to $110 million on HAB activities in just fiscal years 2013 through 2015. NOAA alone spent an estimated $168 million between 2013 and 2021. EPA, NSF, USGS and NIH spend millions more annually on cyanobacteria and cyanotoxin research.
Sources: GAO-17-119; Congressional Research Service Report R46921
STATE
State HAB remediation spending
$135 million
a year for Ohio's H2Ohio program, recently cut by 40 percent
$340 million+
committed by Florida in HAB mitigation grants
Ohio's H2Ohio program spent $135 million annually, recently cut by 40 percent. Florida has committed over $340 million in HAB mitigation grants. Blooms in Lake Erie and Lake Okeechobee continue regardless. Ohio would need an additional $170 to $250 million per year just to meet its phosphorus reduction targets.
Sources: E&E News; WUSF
THE CHEMICAL TRAP
Why chemical algaecides make the problem worse
Chemical algaecides kill cyanobacteria on contact, but they do not remove the phosphorus and nitrogen that caused the bloom. Here is what follows.
1. The nutrients stay
The phosphorus and nitrogen stay in the water and the bloom returns, often stronger.
2. The toxins are released
When the cells are killed they burst open and release their stored cyanotoxins into the water, which makes it more dangerous rather than less.
3. The food chain is dismantled
Algaecides also kill the beneficial algae and phytoplankton that are the primary producers of the lake, along with the zooplankton that graze on them. That dismantles the food chain from the bottom up and removes the very organisms that naturally compete with cyanobacteria and hold it in check.
4. Copper builds up
Copper-based products accumulate in the sediment, contaminating the water body long term.
Source: ScienceDirect, Release of algae organic matter following algaecide application
WHO IS AFFECTED
Who is affected by harmful algal blooms?
If you are connected to freshwater in any way, harmful algae blooms and cyanobacteria affect you. Here is who is paying the price right now.
Lakeside homeowners
You bought your home for the water. Harmful algae blooms are dropping property values 11 to 30 percent and making it unsafe to swim, fish, or let your children play near the shore.
Cities and water utilities
Blooms pose serious liability to municipalities and water utilities. When cyanotoxins contaminate a public supply the consequences are enormous: emergency declarations, lawsuits, infrastructure overhauls costing hundreds of millions, and long-term damage to community health and trust. That exposure grows every year as blooms become more frequent.
Parks and recreation
Beaches and swimming areas are being posted and closed for a growing share of the season. Families are losing their swimming spots to cyanobacteria, and parks departments carry the cost and the risk.
Farmers and ranchers
Excess phosphorus and nitrogen wash off fields into ponds and streams, where they feed cyanobacteria instead of crops. That is lost nutrient and lost money. Beneficial phytoplankton consumes those same nutrients and turns them into more phytoplankton, and during irrigation that phytoplankton-rich water becomes a natural biostimulant that returns the captured nutrients to your soil.
Golf courses
For superintendents, cyanobacteria in the irrigation pond clogs irrigation equipment, degrades turf quality, drives members away with odor, and creates liability when a member's dog drinks from a contaminated pond.
HOAs and communities
That green, smelly pond in the neighborhood is not just unsightly, it is potentially toxic cyanobacteria. Stormwater violations bring fines, and blooms drag down property values across the whole community.
ANOTHER OPTION
A biological solution for harmful algal blooms: Hydralife Compete
Conventional approaches treat the symptom or the watershed. Dredging, alum treatment and watershed nutrient control all work, and all of them are slow, expensive or temporary. Hydralife offers another option: Hydralife Compete, live multi-species beneficial phytoplankton that draws the nutrients out of the water column itself.
Competitive exclusion is the approach Hydralife Compete uses: live beneficial phytoplankton consumes the ammonia, nitrite, nitrate and phosphate that cyanobacteria feed on, 24-7 through the growing season, so the bloom is starved of its food source rather than poisoned. Nothing is applied to kill the cyanobacteria.
THE MECHANISM
Excess nutrients (ammonia, nitrite, nitrate, phosphate) + Hydralife Compete = nutrients consumed, and the bloom is left without its food supply.
Lily Pond in Denver's Washington Park. Its 2026 cyanobacteria advisory was lifted after treatment.
It works in freshwater lakes, ponds and reservoirs of any size. For farms, ranches and golf courses, it captures lost nutrients from runoff and returns them to the soil as a natural biostimulant during irrigation. Nutrient-rich water is not a hard case for this approach. It is the condition it is built for.
9 QUESTIONS
Harmful algal bloom questions, answered
Questions about Hydralife Compete itself, dosing or pricing are answered in the Hydralife Compete FAQ.
What causes harmful algal blooms?
Excess nitrogen and phosphorus feed cyanobacteria, and warm water makes them grow faster and bloom earlier. The nutrients come from agricultural runoff, lawn care products, stormwater drains, aging sewer systems and industrial discharge. EPA's 2022 National Lakes Assessment named nutrient pollution the most widespread stressor in U.S. lakes.
How many U.S. lakes have cyanotoxins?
EPA's 2022 National Lakes Assessment detected microcystins in 50 percent of U.S. lakes, roughly 134,000 of the 268,020 lakes the survey represents, up from 21 percent five years earlier. The millions of small ponds on farms, in neighborhoods and at parks are not tested at all.
Are all algae harmful?
No. Many species of algae and phytoplankton are essential to healthy aquatic ecosystems. What most people call toxic algae is cyanobacteria, a different organism with no cell nucleus. The problem is specifically cyanobacteria and the excess nutrients that feed them.
Can you boil or filter cyanotoxins out of water?
No. Cyanotoxins cannot be boiled out, filtered with a household pitcher filter, or destroyed with chlorine. Boiling ruptures the cyanobacteria cells and releases the toxin held inside them, which is why Toledo residents were told specifically not to boil their water in 2014.
Can you be exposed to cyanotoxins without touching the water?
Yes. Cyanotoxins can become aerosolized, and wind, waves and boat traffic carry them into the air. People living near water with harmful algae blooms report sore throats, coughing and asthma-like symptoms without ever going in. Swallowing the water remains the highest-risk exposure.
How quickly can a harmful algal bloom kill a dog?
Symptoms can appear in as little as one to three and a half hours and progress rapidly to seizures, collapse and death. There is no antidote for cyanotoxin poisoning, and by the time symptoms appear it is often too late for treatment.
How much do harmful algal blooms cost?
Since 2010, U.S. communities have spent more than $1.1 billion on HAB treatment, prevention and remediation across 85 locations in 22 states. NOAA estimates national losses of at least $82 million a year from closed beaches, closed shellfish beds and reduced fishing, and homes on affected lakes lose 11 to 30 percent of their value.
Why do blooms come back after algaecide treatment?
Algaecides kill cyanobacteria but leave the phosphorus and nitrogen that caused the bloom in the water, so the bloom returns, often stronger. The dying cells also release their stored cyanotoxins, and the treatment kills the beneficial phytoplankton and zooplankton that naturally compete with cyanobacteria.
How does Hydralife Compete starve a harmful algal bloom?
Hydralife Compete is live multi-species beneficial phytoplankton that consumes the ammonia, nitrite, nitrate and phosphate cyanobacteria need, 24-7 through the growing season. This is competitive exclusion: nothing is applied to kill the cyanobacteria, and the bloom is left without the food supply it needs to form.
GET STARTED
Find out what is in your water
Every pond, lake and reservoir carries a different nutrient load, and the only way to know yours is to measure it. Tell us about your water body, including its history, size and water source, and send a photo if you have one, and we will recommend a dose and protocol matched to it. Free nutrient testing is available on samples you ship back to us, before and after treatment, so you can verify the drawdown in your own water.
SOURCES
Sources and references
Every figure on this page comes from the following published sources. Links open in a new tab.
EPA, Common Cyanotoxins Produced by Cyanobacteria
EPA, Sources and Solutions: Agriculture
EPA, National Lakes Assessment 2022 Key Findings
CDC, Harmful Algal Blooms and Your Health
CDC, One Health Harmful Algal Bloom System, 2022 Summary Report
CDC, Surveillance for Harmful Algal Bloom Events, 2016 to 2018, MMWR
CDC, Clinical Signs and Symptoms, Freshwater HABs
Oregon Health Authority, Cyanobacteria Blooms FAQ
NOAA, What are the impacts of harmful algal blooms
NOAA, The Untold Story of HABs
GAO, Federal Agencies' Expenditures Related to Harmful Algae, GAO-17-119
Congressional Research Service, Report R46921
WHOI, Control and Treatment of HABs
WHOI, Fish Kills from Freshwater HABs
EWG, Dog Deaths Linked to Harmful Algal Blooms
University of Michigan, Toxic Algae Blooms Lasting Longer in Lake Erie
Cornell Veterinary Medicine, Cyanobacteria Toxicosis in Dogs
PMC, Aerosolized Cyanobacteria in the Human Respiratory Tract
PMC, BMAA and Amyotrophic Lateral Sclerosis
PMC, Canine Dihydroanatoxin-a Mortality in Central Texas
Maryland Department of the Environment, 2022 Fish Kill Summary
Environment America, 2024 Beach Report (Safe for Swimming?)
ScienceDirect, Release of algae organic matter following algaecide application
Ohio Sea Grant, Harmful Algal Bloom Research Initiative
USDA Economic Research Service, Fertilizer Use and Price
Statehouse News Bureau, Toledo water crisis coverage
Oregon Public Broadcasting, Salem drinking water advisory over cyanotoxins, 2018
E&E News, Funding cuts could threaten Lake Erie toxic algae progress
WUSF, New federal funding to help with toxic algae
Grist, What's raising water bills in the Great Lakes? Toxic algae