Harmful Algae Blooms (HABs)

The California State Water Resources Control Board has announced that the occurrence of HABs appears to be increasing. This has led to an increase in the public’s concern regarding potential health impacts to humans and animals, particularly dogs. Please review the attached fact sheet.

What are Harmful Algae Blooms (HABs)?

Algae are tiny, harmless organisms that live naturally in water. A harmful algae bloom (HAB) is actually made of cyanobacteria, sometimes called blue-green algae. Some cyanobacteria species create toxins that can make people and pets sick.

Blue-Green Algae (Cyanobacteria)

Blue-green algae poisoning is most common in pets. Symptoms, including death, can be more severe in pets because they tend to drink the water from affected lakes and reservoirs. Children and adults can experience serious injury to the liver, kidney, and nervous system if affected water is swallowed. Medical treatment should be sought immediately if a person or pet is suspected to have blue-green algae poisoning.

Common recreational water purification techniques, including camping filters, tablets, and boiling, do not remove toxins from affected water.

When In Doubt Stay Out

Know the signs of an algae bloom. Don’t go in water that is foamy, scummy, thick like paint, pea-green, blue-green or brownish red.

Reporting an Algae Bloom

  • To report a bloom, or an animal or human illness related to a bloom, contact the California State Water Resources Control Board at 916-341-5357 or email the board. Or fill out this Harmful Algal Bloom Report Form online.

  • For health-related questions, call Napa County Public Health at 707-253-4270.

  • For assistance with reporting waters that may be affected by a harmful algal bloom, call Napa County Environmental Health at 707-253-4417.

HAB Public Education Campaign

Napa County Environmental Health, in coordination with Public Health, launched a public education campaign on seasonal algal blooms in the Spring. They have provided posters [English HABs poster (PDF) / Spanish HABs poster (PDF)] to various agencies to post up and down the valley.

Additionally, as part of the campaign, Public Health reached out to the veterinary community and Environmental Health provided brochures [English HABs brochure (PDF) / Spanish HABs brochure (PDF)] as a handout to the Animal Shelter. The HABs brochure was also provided to Napa County Regional Park and Open Space District, to offer whenever they set up booths.

More Information

Find more information about Harmful Algae Blooms (HABs) at this HABs Frequently Asked Questions page from the California State Water Resources Control Board.

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