Most of the air we breathe comes from algae and other aquatic organisms that have been photosynthesizing sunlight into oxygen for a billion years. But not all algae are life-giving. Blue-green algae contain a powerful class of toxins called cyanotoxins. When these algae form blooms — rapid accumulations of algae in fresh or marine water — they can damage ecosystems and cause vomiting, fever, headache, neurological problems, and even death in humans and animals. 

These poisonous organisms have been cropping up a lot lately. Beaver Lake in Asheville, North Carolina, was closed last week after local officials found toxic algae in the water. Three dogs died from playing on a beach suspected to be contaminated with toxic algae on the Columbia River in Washington state last month. In California, the Bureau of Land Management closed a 28-mile stretch along the Merced River after water samples south of where a family of hikers mysteriously died in August showed high levels of toxic algae. These types of incidents are not rare. A new study from the Centers for Disease Control and Prevention estimates that toxic algae sent more than 300 Americans to the emergency room between 2017 and 2019. 

But despite the dangers of algae-related poisoning and the harmful and costly impacts of blooms on ecosystems, the federal government doesn’t have a cohesive strategy for dealing with freshwater harmful algal blooms, or HABs. That’s the conclusion of a new watchdog report from the U.S. Environmental Protection Agency’s Office of Inspector General. “The EPA does not have an agency-wide strategy for addressing harmful algal blooms,” the report says, “despite Congress appointing the EPA administrator as the leader for federal actions focused on reducing, mitigating, and controlling freshwater HABs.” The report recommends that the EPA needs to focus on developing a national program to “forecast, monitor, and respond” to these blooms; establish new water safety criteria for algae-causing chemicals in lakes, rivers, and streams; and take a closer look at whether water with algae in it is safe to drink. 

Algal blooms are sparked by nutrients, an umbrella term for the chemical elements phosphorus and nitrogen, which are often used by farmers to fertilize their fields. Nutrients can also come from other sources, like chemically treated water from wastewater plants and water from storm drains containing a cocktail of urban pollution. Atmospheric pollution from fossil fuel plants and cars can seed algal blooms, too.  

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Climate change also fuels blooms, albeit more indirectly. Research shows that algae thrive in bodies of water warmed by climate change. And erratic weather like intense tropical storms and extreme rainfall, byproducts of a warming planet, serve as catalysts for new blooms by helping nutrients leach into bodies of water and moving algae around. Blue-green algae, also known as cyanobacteria, particularly like it when heavy rain is followed by a big drought — a pattern that’s becoming more common with climate change — because the rain pushes algae downstream into new areas and then drought forces that water and the algae in it to stagnate, which then allows the algae to proliferate unchecked. “It’s the perfect storm scenario for cyanobacteria,” Hans Paerl, a professor of marine and environmental sciences at University of Carolina, Chapel Hill, told Grist.

As the risk of harmful blooms grows, the EPA has been more or less asleep at the wheel, according to the watchdog report. According to the report, the agency has been chipping away at the HABs problem little by little, by investigating localized blooms in individual states and collecting water data from the public to be used for better monitoring, among other small-scale initiatives. But the EPA has not invested in expanding these efforts into a national algae monitoring network. The report notes that the EPA has also not exercised its full authority to regulate HABs under the Clean Water and Safe Drinking Water acts. 

In 2015, Congress put the EPA in charge of developing informational drinking water health advisories for cyanotoxins. Exposure to even low doses of the toxins over a long period of time can encourage liver tumors and other disease. But the report notes that the agency still hasn’t developed those advisories. Experts say the EPA should go a step further and set maximum contaminant limits, a legal threshold on the amount of a substance that is allowed in public water systems under the Safe Drinking Water Act, for cyanotoxins, which would require states to meet those standards for their drinking water supplies. Only two states, Oregon and Ohio, have forged ahead without the EPA and regulated cyanotoxins in drinking water. Until the EPA releases a set of federal standards, most states won’t monitor their drinking water supplies for these toxins. “If you think about how people respond to regulations in general, they typically step up to the plate to meet what regulations are on the books,” Christine Kirchoff, associate professor of water policy and management at the University of Connecticut, told Grist. “And there aren’t regulations for cyanotoxins except in those two states.” 

In the EPA’s defense, there isn’t a ton of research on the public health effects of algal contaminants in drinking water. It’s difficult for the EPA to amass enough evidence to determine which thresholds of algae in drinking water are safe or not safe.

In response to the inspector general report, EPA officials said they plan to “explore the potential for new or revised numeric nutrient criteria” — in plain English, standards for nutrients in waterways like lakes and rivers — by the end of 2022. But the inspector general said that wasn’t good enough and that the EPA should make a more concrete plan. Outside experts agree with that.  

“Even though the EPA’s HABs program is getting better and more involved, it’s still not up to the scale of the problem,” Donald Anderson, a biologist at the Woods Hole Oceanographic Institution, told Grist. He wants the EPA to work with the National Atmospheric and Oceanic Administration, which is the agency in charge of monitoring HABs in marine environments, so that the programs can inform one another. And he thinks that Congress needs to not just authorize the EPA to lead the nation’s response to HABs, but also ensure that the agency is getting enough money, or congressional appropriations, to sufficiently address the problem. “There really isn’t a recurrent funding program in the EPA on multiple areas of HAB research,” he said. “It’s a little more piecemeal, hit and miss.” 

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Paerl said the EPA could be more aggressive about collecting and disseminating data on HABs. “The role the EPA really needs to play is to bank the data, so to speak, and then from that develop strategies that can be used across the U.S.,” he said. Some of the areas that are prone to blooms, like agricultural watersheds, stretch across multiple states, which means that effectively addressing those blooms will require an interstate response. 
The EPA can draw inspiration for its HABs program from the few states that have put successful strategies in place already. In Ohio, for example, state legislators passed a bill preventing farmers from applying fertilizer to saturated ground or if the forecast says the chance of 1 inch of rain over the next 12 hours is greater than 50 percent. A regulation like that on a much wider scale could help stem the flow of nutrients into waterways. “What we need to do is known, it’s just sort of getting the regulatory push to do it,” Kirchoff said.