Toxic Algae

Lakes, reservoirs, rivers and streams are critical sources of drinking water for millions of Americans. They also provide recreational opportunities and wildlife habitat.

Now many of these water bodies are threatened by a growing phenomenon known as algae blooms, fueled largely by polluted runoff from farms and exacerbated by climate change. Algae blooms wreak havoc on ecosystems, and the cyanobacteria that make up these outbreaks sometimes produce poisonous byproducts called cyanotoxins. Ingestion of or even just exposure to these toxins has been associated with many human health issues, ranging from diarrhea to cancer, as well as with pet and wildlife deaths.

Currently, no government agency publicly tracks toxic algae outbreaks nationally. To fill this gap and help policymakers and consumers understand and quantify the impact of toxic algae blooms on drinking water, recreation, public health and the environment, EWG is monitoring and mapping all related news reports across the U.S. since 2010.

If you see algae that is bluish-green or looks like pea soup in a lake or other water body, contact the local health department to let them know and have it tested for toxins. You can also reach out to local media to try to get coverage of the issue.

Check out our map here.

 

View photos of algae blooms here.

Location of algal blooms from 2010 to May 2019

Thursday, June 6, 2019

Toxic algae blooms are a growing epidemic, polluting lakes and other waterways across the U.S., as a 2018 EWG report revealed. They can occur any time, but they thrive when water is warmer, usually from May through October.   

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News and Analysis
Article
Tuesday, May 28, 2019

With peak toxic algae bloom season underway, the Environmental Working Group is releasing an updated map of all algae outbreaks reported in the U.S. since 2010. In coming months, the map will be updated weekly, providing comprehensive tracking of this growing nationwide hazard.

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News Release
Wednesday, April 24, 2019

Private wells across Iowa are contaminated with unsafe levels of two agricultural contaminants, according to an investigation by the Environmental Working Group and the Iowa Environmental Council.

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News Release
Tuesday, April 9, 2019

Across America, outbreaks of toxic algae, triggered by polluted farm runoff, are increasing in frequency and severity, fouling drinking water with dangerous toxins. In 2014, an algae outbreak in Lake Erie contaminated the tap water for 500,000 people in and around Toledo, Ohio, rendering it unsafe to drink for three days. 

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AgMag
Article
Tuesday, April 9, 2019

Unregulated animal factory farms are funneling nutrient-rich pollution into Lake Erie, feeding an enormous toxic algae bloom each summer, according to a new investigation by the Environmental Working Group and the Environmental Law & Policy Center.

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News Release
Monday, April 8, 2019

The Maumee River, overloaded with fertilizer and manure, is the single largest source of the phosphorus that triggers blooms of toxic algae in Lake Erie. Over half of the manure in the Maumee River watershed comes from an exploding number of unregulated factory farms, a new EWG and Environmental Law & Policy Center investigation reveals.

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Reports & Consumer Guides
Wednesday, April 3, 2019

Outbreaks of toxic algae in U.S. waterways usually happen in warmer months. But in a sign that the problem is growing worse, algae blooms were reported in December in Michigan and Washington state, with another reported in Florida during the first days of spring.

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News and Analysis
Article
Tuesday, October 9, 2018

Outbreaks of potentially toxic algae in U.S. lakes, rivers and other waterways rose by an additional 40 percent this year compared to 2017, according to EWG’s tracking of news reports. 

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AgMag
Article
Tuesday, September 18, 2018

This summer, EWG is tracking outbreaks of potentially toxic algae across the U.S. We have been startled to find that these outbreaks are erupting everywhere: from the East Coast to the West Coast, from the Great Lakes to the Gulf of Mexico.

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News and Analysis
Article
Friday, September 14, 2018

Outbreaks of potentially toxic algae in U.S. lakes, rivers, streams and even the Gulf of Mexico continue to rise sharply this summer, according to EWG’s ongoing tracking of algae outbreaks.

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Key Issues:
AgMag
Article
Friday, August 31, 2018

An unprecedented environmental catastrophe is striking Florida’s storied beaches, lakes and rivers this summer. Outbreaks of three separate strains of harmful algae are killing fish and other marine animals, threatening public health and devastating recreation and tourism.

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AgMag
Article
Friday, August 10, 2018

Outbreaks of potentially toxic algae are rising sharply this summer in lakes, rivers and streams in the U.S., according to EWG’s ongoing tracking of algae outbreaks.

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AgMag
Article
Friday, June 29, 2018

Millions of people could be exposed to potentially toxic algae blooms this July Fourth holiday.

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AgMag
Article
Wednesday, May 30, 2018

Across the U.S., there is a growing epidemic of harmful algal blooms – also known as blue-green algae – polluting lakes, rivers and swimming holes, EWG reported this month.

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Children's Health
Article
Wednesday, May 16, 2018

In 2010, there were just three reports of toxic blooms in the U.S. In 2015, there were 15, including the largest to date in Lake Erie, although the bacteria did not get into Toledo’s drinking water. In 2016, there were 51, including a huge bloom in Florida that prompted the state to declare an emergency in four counties on the Atlantic Coast. Last year, 169 blooms were reported. And in March, Ohio Gov. John Kasich declared the open waters of western Lake Erie “impaired for recreation” – an unprecedented designation that under the federal Clean Water Act will require the development and enforcement of plans to reduce toxic blooms.

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Reports & Consumer Guides
Tuesday, May 15, 2018

In 2014, Toledo was the first U.S. city where a toxic algal bloom made tap water unsafe to drink. But it may not be last, says a new report by the Environmental Working Group.

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News Release
Tuesday, May 15, 2018

Across the U.S., a growing epidemic of toxic algal blooms is polluting lakes and other waterways, according to a new report by the Environmental Working Group.

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News Release
Thursday, September 8, 2016

From Florida beaches to Lake Erie to the California Delta, algal blooms threaten human health and aquatic ecosystems. Cyanobacteria, commonly known as blue-green algae, produce toxins that can make people sick and even kill pets.
 

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Key Issues:
AgMag
Article
Thursday, June 30, 2016

What comes to mind when you think of the Florida coast? Sandy beaches, sunshine, warm water and … toxic algal blooms? 

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AgMag
Article
Friday, October 9, 2015

Ripped from the pages of an obscure science fiction novel, millions run screaming from the threat of a toxic algal bloom blanketing almost 650 miles of the Ohio River. Regrettably, this story isn’t made up. Officials in the Ohio River basin are scrambling to deal with poisonous slime that may compromise the safety of drinking water, suffocate aquatic life and halt recreational activity for much of the region.

 

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AgMag
Article
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