Harmful algal blooms (HABs) also occur in the ocean, and can cause illnesses in humans and animals. This page provides an overview of potential marine HAB illnesses, precautions to reduce exposure, and how to report any potential illnesses that may occur.
Harmful Algal Blooms (HABs)
OEHHA performs risk assessment and hazard evaluation activities relating to Harmful Algal Blooms (HABs) in lakes, rivers, and ocean environments. An algal bloom is a rapid growth of algae and/or cyanobacteria (also known as blue-green algae) in water. An algal bloom is harmful when the algae or cyanobacteria produce toxins that can adversely impact humans, wildlife, or domestic animals. Non-toxic algal blooms are harmful when they adversely impact the aquatic ecosystem through crowding out other species, depleting dissolved oxygen, or disrupting other ecological factors.
OEHHA’s work focuses on the toxic impacts of HABs on humans and animals. Marine HABs commonly consist of an overgrowth of certain types of algae (diatoms or dinoflagellates) that produce biotoxins. HABs commonly found in California freshwater and estuarine environments are a type of photosynthetic bacteria (cyanobacteria) that can produce cyanotoxins. Factors promoting HABs include warmer temperatures and excess nutrients. Currently, OEHHA’s work on HAB-related toxins focuses on consumption of contaminated seafood, exposure during swimming and other recreational water activities, and their impacts on the health and well-being of humans, domestic animals, fish and invertebrates, and wildlife.
OEHHA’s work relating to HABs includes:
Marine HABs
Freshwater and Estuarine HABs
- See what HABs look like (pdf)
- Learn what you can do to protect yourself
- Cyanotoxins in recreational waters
- Freshwater and estuarine HAB-related illness tracking (CA HABs Portal)
- May 6, 2021 Notice of Availability of Notification Level Recommendations for Four Cyanotoxins in Drinking Water
- Jun 16, 2022 Notice of Availability of Acute Notification Level Recommendations for Four Cyanotoxins in Drinking Water
HABs News
Las proliferaciones de algas nocivas marinas (HAB, por sus siglas en inglés) también ocurren en el océano y pueden causar enfermedades en seres humanos y animales. Esta página proporciona una descripción general de las posibles enfermedades asociadas con la proliferación de algas nocivas marinas, las precauciones para reducir la exposición y cómo informar cualquier enfermedad potencial que pueda ocurrir.
Blue-green algae (also known as cyanobacteria) are non-pathogenic photosynthetic bacteria that grow in outdoor water bodies and produce toxins such as microcystins, cylindrospermopsin and anatoxin-a. This fact sheet is meant to help veterinarians with diagnosis and treatment options.
On Tuesday July 30, 2019, OEHHA hosted the Domoic Acid Webinar: Research on Effects of Repeat Low-Level Exposures and Its Implications for Human Toxicity. A recording of the webinar and transcript of the audio portion are now available.
Preguntas frecuentes sobre el ácido domoico en pescado y mariscos, consejos sobre cómo puede reducir su riesgo, y dónde puede apprender más información.
Frequently asked questions about domoic acid in seafood, tips on how to reduce your risk, and where to find more information
Health risk information on cyanobacteria (blue-green algae) for dog owners near lakes, ponds, and rivers.
Bringing attention to the upcoming harmful algal bloom (HAB) season and offering assistance for responding to HAB-related illnesses in animals. Requesting assistance with reporting HAB events and HAB-related human and animal illnesses to the state centralized system.
Bringing attention to the upcoming harmful algal bloom (HAB) season and offering assistance for responding to blooms. Requesting assistance with reporting HAB events and HAB-related human and animal illnesses to the state centralized system.
Bringing attention to the upcoming harmful algal bloom (HAB) season and to offering assistance for responding to blooms. Requesting assistance with reporting HAB events and HAB-related human and animal illnesses to the state centralized system.