Red Tides in Florida: Current Legislation and Litigation Efforts
Anna Nguyen
- Introduction
“Red tides,” also known as harmful algae blooms (HABs), have devastating impacts on the environment.[1] These blooms occur when algae grows out of control, producing toxic effects on the ecosystem and humans and often turning the water red.[2] Human activity has increased the frequency of these events, though they typically happen yearly on Florida’s Gulf Coast.[3] This post examines efforts to mitigate and reduce red tides, including key legislative efforts and relevant legal disputes. It primarily focuses on Florida, as the Florida Gulf Coast is the region the most regularly impacted by red tides.[4]
- Background on Red Tides
Red tides occur in every U.S. coastal state, but they are the most severe and frequent in the Gulf Coast. These events have become increasingly frequent, with severe blooms lasting up to 18 months.[5] For example, in February 2025, a 200-mile long red tide formed along the Southwest Florida coast.[6] Red tide is harmful because it negatively impacts local ecosystems, public health, and a region’s economic activity.
Red tide harms local ecosystems because it produces toxins that may kill marine animals. The red tide works in two ways: by releasing brevetoxins, which harm the nervous system of marine life and through algae decomposition, which depletes oxygen in the water. For example, in Florida, the algal toxin Karenia brevis,which causes brevetoxins, leads to “massive fish kills, sea turtle and sea bird mortalities and impacts on benthic communities including sea grass and coral community die offs.”[7] Further, the mass deaths of marine life causes altered food web interactions, which further decreases marine life.[8] The damage is easily seen from land, as impacts such as massive fish kills leave beaches littered with decaying marine life. For instance, a 1996 red tide in Florida led to the death of approximately 10% of Florida’s manatee population.[9]
The harmful bloom also affects public health. Generally, exposure to red tide may cause respiratory issues, and skin irritation.[10] In rare cases, eating toxic shellfish that have been exposed to red tide can cause muscular paralysis and respiratory difficulty issues (though shellfish sold in markets are usually screened for HAB toxins beforehand).[11]
Further, red tides have caused significant economic damage. For instance, red tides cause swimming to become unsafe, which discourages beach tourism. A University of Central Florida Rosen College Study estimated that the 2018 Florida Red Tide caused $2.7 billion in losses due to decreased revenue for coastal businesses.[12] These economic impacts can be seen in the fishing industry. Another study found that during a red tide, the fishery and seafood sector of Pinellas County, FL generated northwards of $20,000 less revenue.[13] Thus, these environmental, public health, and economic harms create strong incentives for lawmakers to pursue red tide mitigation policies.
Although red tides occur naturally, human activity has caused them to be more frequent. Chemical runoff from activities such as farming, factories, and sewage treatment plants flow into the ocean, increasing nutrients in the water and causing algae to bloom excessively. This phenomena leads to red tides.[14] Researchers at the University of Florida found that human activity has played a consistent role in intensifying red tides during the past decade. In particular, nitrogen inputs prolong red tides.[15] Moreover, climate change can worsen red tides because of warming water temperatures, higher carbon dioxide levels, and other factors.[16] Limitations to this research exist, however, as many factors contribute to a red tide.[17] Thus, finding a causal link between human activity and red tides is challenging for researchers.[18]
- Efforts to Mitigate Red Tides
At the federal level, the primary legislation targeting the red tide is the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA).[19] Congress enacted the HABHRCA in 1998. In 2018, Congress expanded the HABHRCA to allow the National Oceanic and Atmospheric Administration (NOAA) to advance scientific understanding and pursue mitigation research to predict HABs.[20] Most recently in 2025, the HABHRCA was reaffirmed. The 2025 version of the HABHCRA appropriates $27.5 million annually (2026 to 2030) to “reauthorize and expand activities administered by [NOAA] and the
Environmental Protection Agency related to research, observation, and control of harmful algal blooms and hypoxia.”[21] Further, the legislation appropriates $2 million to address HABs that have a detrimental effect on a state’s environment, economy, or public health.[22] The 2025 HABHCRA adds the Department of Energy to the inter-agency task force which was established by the original 1998 HABHRCA. Currently, NOAA and the Environmental Protection Agency (EPA) co-chair the Interagency Working Group for HABHRCA (IWG-HABHRCA). The IWG-HABHRCA heads various research funding efforts to mitigate and control red tide.[23]
The HABHRCA also implements collaboration between federal and state governments. The 2025 version amends the law to “examine, in collaboration with State and local entities and Indian Tribes . . . the causes, ecological consequences, cultural impacts, and social and economic costs of harmful algal blooms and hypoxia[.]”[24] Further, the act supports observations data of HABs by providing competitive grant funding to state and local entities.[25] Also, as mentioned, the act provides $2 million to reimburse states and local entities for costs associated with a HAB event that has had significantly detrimental impacts. Further, the South Florida Clean Coastal Waters Act of 2021[26] which amended HABHRCA, exemplifies cooperative federalism. The Act requires the IWG-HABHRCA to create a plan to tackle HAB issues in South Florida.[27]
Overall, the HABHRCA provides useful methods for mitigating and reducing the impacts of red tides through interagency cooperation and collaboration. Since the HABHRCA primarily implements collaboration and extends funding to mitigate the harmful bloom, it does not have a cause of action mechanism to hold those accountable who may be contributing to the red tides. Instead, environmentalists can sue under other environmental laws.
As mentioned, increased human activity has caused red tides to happen more frequently.[28] Fertilizer and sewage runoff from industries can lead to increased algae blooms and the prolonged duration of red tides. Potential litigants can sue under the Clean Water Act (CWA)’s citizen suit provision to hold polluters accountable. For example, the Piney Point phosphogypsum stack, a large waste site in Florida, leaked 215 million gallons of contaminated water into Tampa Bay.[29] Conservation organizations raised concerns about HABs due to the leak and filed a lawsuit against the Florida Department of Environmental Protection (FDEP) and HRK Holdings (owners of Piney Point) for violating the CWA.[30] In 2024, a settlement agreement was reached, and the FDEP agreed to pay for water quality monitoring around Tampa Bay and post future reports of pollution leaving the Piney Point facility. HRK Holdings was found liable and paid $846,900 in damages.[31]
Potential litigants may also sue under the Endangered Species Act (ESA). In a 2020 case in the Southern District of Florida, the Center for Biological Diversity sued the U.S. Army Corps of Engineers (Corps), alleging that the Corps likely causes or contributes to HABs by releasing fresh water from Lake Okeechobee in an effort to regulate water levels.[32] Plaintiffs claim that this release of fresh water causes upland run-off leading to red-tide blooms, which harm endangered species. Plaintiffs sought injunctive relief to permanently enjoin the Corps from continuing this practice.[33] This case resulted in a settlement agreement and a voluntary dismissal from the parties.
A recent case in the Middle District of Florida also involved a claim under the ESA. Bears Warriors United, Inc. alleged that the FDEP was the proximate cause of manatee takings because of the impact of one of the Department’s practices on HABs. The case concluded that wastewater discharges that the FDEP had regulatory control over resulted in HABs causing the death of seagrasses that manatees depend on for food.[34] Following the bench trial, the court issued an injunction requiring the FDEP to obtain an incidental take permit. An incidental take permit requires the FDEP to establish a conservation plan to mitigate the harm to impacted species during a specific activity.[35]
- A “Citizen Suit” Provision of the HABHRCA?
As mentioned, the HABHRCA does not have a mechanism for litigants to sue under. A potential enforcement mechanism under the HABHRCA could mirror the citizen-suit provision in the CWA.[36] Regulations, perhaps created by the IWG-HABHRCA, could require industries to take stricter preventative measures to reduce and mitigate pollutant runoff. The regulations could be more stringent for industries that are near waterways, where pollutant run-off could affect algae blooms.[37]
However, this raises the question of what the point of this would be since the CWA already allows for this. Perhaps the HABHRCA could provide for greater statutory penalties if a polluter is found liable for causing a red tide. Considering the mass destruction of wildlife and the economic and public health penalties of a red tide, there may be a large policy incentive to bring harsher punishments against polluters.
But there are a few hurdles. For instance, it may be difficult to prove causation since there are various factors that contribute to red tides. Litigants will also likely face high costs during discovery and need expensive expert testimony to attempt to establish a clear link (if any) between a polluter and a red tide.
- Conclusion
In sum, polluters and the government may be held liable under laws such as the CWA or ESA. The plaintiffs in these actions are generally environmental impact litigation groups, while the defendants are generally either the state or federal agencies or industry polluters. Further, red tides seem to be pointed to as a potential injury, rather than a cause of action itself, i.e. plaintiffs sue industries for non-compliance with the CWA, rather than directly causing a red tide. An enforcement mechanism under the HABHCRA could help mitigate and prevent red tides, though it may be difficult to hold a polluter liable for a red tide as many factors contribute to algae blooms.[38] Additionally, the HABHCRA is structured for interagency collaboration and cooperative federalism, rather than holding polluters accountable. Thus, those concerned about red tides in Florida will have to rely on the research and mitigation efforts of agencies or the lawsuits brought by environmentalist groups. However, as environmental concerns worsen i.e. climate change, lawmakers will hopefully have strong economic, environmental, and health incentives to create strong policies mitigating the red tide.
[1] What is a Red Tide?, Nat’l Oceanic and Atmospheric Admin. (June, 16, 2024), https://oceanservice.noaa.gov/facts/redtide.html.
[2] Harmful Algae Blooms, Nat’l Oceanic and Atmospheric Admin. (Feb. 25, 2025), https://oceanservice.noaa.gov/hazards/hab/.
[3] Id.
[4] What is a Red Tide?, Nat’l Oceanic and Atmospheric Admin. (June, 16, 2024), https://oceanservice.noaa.gov/facts/redtide.html.
[5] Id.
[6] Tom Bayles, Swath of red tides forms along Southwest Florida coast to Tampa Bay to Key West, WGCU (Feb. 2, 2025), https://www.wgcu.org/section/environment/2025-02-02/swath-of-red-tide-forms-along-southwest-florida-coast-from-tampa-bay-to-key-west.
[7]R.H. Pierce & M.S. Henry, Harmful algal toxins of the Florida red tide (Karenia brevis): natural chemical stressors in South Florida coastal ecosystems, Ecotoxicology 623 (2008).
[8] Ecosystems, U.S. Nat’l Off. for Harmful Algal Blooms, https://hab.whoi.edu/impacts/impacts-ecosystems/.
[9] START1, The Harmful Effects of Red Tide, Solutions to Avoid Red Tide Preserving Our Coastal Waters, https://start1.org/red-tide/effects/.
[10] Clinical Signs and Symptoms Caused by Saltwater Harmful Algal Blooms, Ctrs. for Disease Control (Feb. 24, 2025) https://www.cdc.gov/harmful-algal-blooms/hcp/clinical-signs/symptoms-saltwater-harmful-algal-blooms.html.
[11] Red Tide (Paralytic Shellfish Poisoning), Commonwealth of Massachusetts, https://www.mass.gov/info-details/red-tide-paralytic-shellfish-poisoning.
[12] Holly Robbins, UCF Rosen College Study Reveals Economic Impact of Florida’s Red Tide on Tourism, UCF Today (Jan. 23, 2024), https://www.ucf.edu/news/ucf-rosen-college-study-reveals-economic-impact-of-floridas-red-tide-on-tourism/.
[13] Andrew Bechard, Economics losses to fishery and seafood related businesses during harmful algal blooms, Fisheries Rsch. (2020).
[14] What is a Red Tide? Nat’l Oceanic and Atmospheric Admin. (June, 16, 2024), https://oceanservice.noaa.gov/facts/redtide.html.
[15] Blake Trauschke, Human activity ‘helped fuel’ red tide events, new study reveals, Univ. of Florida (April 7, 2022), https://news.ufl.edu/2022/04/red-tide-study/.
[16] Climate Change and Freshwater Harmful Algal Blooms, Environmental Protection Agency, https://www.epa.gov/habs/climate-change-and-freshwater-harmful-algal-blooms.
[17]Id.
[18]Id.
[19] An Interagency Approach to Harmful Algal Bloom and Hypoxia Research and Control, Nat’l Ctrs. for Coastal Ocean Science, https://coastalscience.noaa.gov/science-areas/habs/habhrca/.
[20] Ecosystems, Nat’l Oceanic and Atmospheric Admin., https://hab.whoi.edu/impacts/impacts-ecosystems/.
[21] 33 U.S.C. § 4002.
[22] Id.
[23] Id.
[24] Id.
[25] Id.
[26] South Florida Clean Coastal Waters Act of 2021, Pub. L. No. 117-144, 136 Stat. 1266, 1267 and 1268.
[27] An Interagency Approach to Harmful Algal Bloom and Hypoxia Research and Control, Nat’l Ctrs. For Coastal Ocean Science, https://coastalscience.noaa.gov/science-areas/habs/habhrca/.
[28] See infra discussion in the introduction.
[29] 3 years after Piney Point, Tampa Bay News, https://www.tampabay.com/news/environment/2024/07/09/piney-point-red-tide-florida-manatee-county/.
[30] Id.
[31] Former Piney Point Owner Liable for Tampa Bay Pollutoin Tied to Massive 2021 Fish Kill, Ctr. For Biological Diversity (Sept. 19, 2024) https://biologicaldiversity.org/w/news/press-releases/former-piney-point-owner-liable-for-tampa-bay-pollution-tied-to-massive-2021-fish-kill-2024-09-19/.
[32] Ctr. for Biological Diversity v. U.S. Army Corps of Eng’rs, No. 19-CV-14199, 2020 WL 9073339, at *1 (S.D. Fla. Aug. 28, 2020).
[33] Id.
[34] Bear Warriors United, Inc. v. Lambert, 778 F. Supp. 3d 1242 (M.D. Fla. 2025).
[35] Permits for Native Endangered and Threatened Species, U.S. Fish and Wildlife Service, https://www.fws.gov/library/collections/permits-native-endangered-and-threatened-species.
[36] Guide to Clean Water Act Citizen Suits, Cᴀʟɪғᴏʀɪɴᴀ Sᴛᴀᴛᴇ Wᴀᴛᴇʀ Rᴇsᴏᴜʀᴄᴇs Cᴏɴᴛʀᴏʟ Bᴏᴀʀᴅ, https://www.waterboards.ca.gov/water_issues/programs/swamp/docs/cwt/guidance/112a1.pdf.
[37] See infra discussion on Background of Red Tides.
[38] See infra discussion on Background of Red Tides.