NRDC Map and Report Reveal Rise in Harmful Algal Blooms

Outbreaks in every state; Industrial Agriculture is helping to fuel the problem

WASHINGTON – As harmful algal blooms (HABs) proliferate in the United States, two new releases from the Natural Resources Defense Council (NRDC) illuminate the scale of the problem nationally and detail a major pollution source helping to fuel it. A new interactive map released today reveals how freshwater bodies throughout the country have been impacted by the explosive growth of algae which can create dead zones that squeeze life out of the rivers, lakes and other waterways. Additionally, a new report dives deep into data on concentrated animal feeding operations (CAFOs), a growing source of the water pollution fueling these outbreaks. Both make clear that authorities have failed to collect and track data needed for proper enforcement of water pollution safeguards nationally.

"We are seeing harmful algal blooms across the country," said Kate Poole, Senior Director of the Water Division at NRDC. "Some, like the Gulf Dead Zone and Lake Erie's blooms are visible from space and make clear that significant change is needed. These materials come, not just at a moment where we aren't even capturing the data needed to address the problem, but the Trump Administration is doing its darnedest to roll back the water pollution protections everyone relies upon."

The new NRDC algal bloom interactive map shows how harmful algal blooms increased in freshwater ecosystems across the nation posing a growing threat to public health. The map shows a range of inefficiencies across state freshwater HAB programs, including the lack of websites to inform the public about the dangers of harmful algal blooms, reporting mechanisms so the public can report outbreaks in their communities, and protocols for how states should respond to harmful algal blooms.

“National headlines this summer warned about harmful algal blooms that expanded across water bodies, killing family pets and sickening people,” said Arohi Sharma, Policy Analyst on Water and Agriculture at NRDC. “This nasty phenomenon will worsen as climate change creates the perfect breeding place for toxic bacteria. The Trump Administration is making it harder to fight this by rolling back clean water protections and allowing livestock operations to go unmonitored, and that does not diminish states’ responsibility to take the problem seriously and invest in proactively reducing the nutrient runoff that fuel harmful algal bloom growth.” 

At the root of the problem are excess nutrients entering waterways. NRDC’s report, “CAFOS: What We Don’t Know is Hurting Us,” tracks states’ access to information on Concentrated Animal Feeding Operations (CAFOs), which would enable those states to assess how livestock operations harm surrounding communities. It further identifies the need to have adequate information to properly regulate how facilities manage manure and the nitrogen and phosphorus it contains. The report reveals how the EPA knows little about CAFOs’ location, number of animals confined, amount of waste they produce, and method for disposing their waste. In response, NRDC created a sample Clean Water Act permit that would allow states to better collect and share CAFO data to the public. The permit would further require facilities to better communicate with the public. 

Jon Devine, Director of Federal Water Policy at NRDC noted, “Information about these facilities is outdated, significantly incomplete, and inconsistent across states. Nutrient pollution from animal factories is therefore highly unregulated. The scope of this problem is vast, and authorities must be able to identify the pollution source to properly diagnose the rise in harmful algal blooms.” 

The common denominator in NRDC’s findings is government’s failure to effectively do its job. As a result, waterways are polluted, and we are seeing an increase in anomalies like harmful algal blooms. 

“CAFOs are major polluters and officials should collect information on them like they do for any other industry of comparable scale,” said Valerie Baron, Staff Attorney on Health and Food at NRDC. “Whether a citizen has access to information on a major health threat in their watershed shouldn’t depend on which state they live in; EPA should protect everyone.”

Link to Map:

Link to Report:

Relevant Blogs:

  1. Big Ag is Hiding in Plain Sight and It’s Making Us Sick
  2. What’s Lurking in Your Lake? NRDC State HAB Program Report
  3. Is Your Favorite Waterway Facing the Threat of Toxic Algae?
  4. Freshwater Flows, Reduced Diversions Help Abate Toxic Algae
  5. Don’t Stop to Smell These (Harmful Algal Blooms)
  6. How Healthy Soil Can Help Reduce Harmful Algal Blooms
  7. How the Clean Water Act Can Combat Harmful Algal Blooms
  8. A Lack of Balance: Runoff and Harmful Algal Blooms


The Natural Resources Defense Council (NRDC) is an international nonprofit environmental organization with more than 3 million members and online activists. Since 1970, our lawyers, scientists, and other environmental specialists have worked to protect the world's natural resources, public health, and the environment. NRDC has offices in New York City; Washington, D.C.; Los Angeles; San Francisco; Chicago; Bozeman, Montana; and Beijing. Visit us at and follow us on Twitter @NRDC

Related Issues
Fresh Water

Related Press Releases