Algae are naturally-occurring microscopic organisms that are found in fresh and salt waters of Virginia and around the world. Many are beneficial because they are major producers of oxygen and food for many of the animals that live in these waters. Algae blooms can occur when warm water and nutrients combine to make conditions favorable for algae growth. Excessive rain typically results in nutrient-runoff from the land that can trigger algae blooms in natural waters.

Most algae species are harmless; however, some species may produce irritating compounds or toxins. These toxins can cause skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting and diarrhea in humans, particularly children, and pets.

Discolored water or scums that are green or blueish-green should be avoided, as they are more likely to contain toxins. Scums are more likely to occur in coves, shallow areas, or along the shoreline.

Dominion Energy, in collaboration with the Virginia Department of Health (VDH), has a sampling plan to evaluate reports of suspected Harmful Algae Blooms in the WHTF. When a suspected HAB is reported or observed, the company's Corporate Biology group gathers samples and tests them based on VDH's sampling protocol. Dominion Energy Corporate Biology staff has been added to VDH's list of recipients of Harmful Algae Bloom reports in Virginia.

The company and VDH advise reporting suspected HABs on Lake Anna and in the WHTF by filling out the Harmful Algae Bloom Online Form. To report health effects only, call the VDH hotline at 888-238-6154.

As a result of testing and evaluation performed in accordance with current Virginia Department of Health guidelines, all “no-swimming” advisories for the Waste Heat Treatment Facility have been lifted as of July 25, 2019. Recreational users of the Waste Heat Treatment Facility are advised to remain on alert for all algae blooms. If water is discolored, has an odor, or if there appears to be a film on the water surface, swimming is not advised for humans or pets.

WHTF HAB Monitoring Map

To report health effects, contact the HAB Hotline: 888-238-6154

To report suspected HABs, fill out the Harmful Algae Bloom Online Form (do not use this form to report health effects).

To prevent illness, people should:

• Avoid contact with any area of the lake where there is scum or an advisory sign is posted.
• Do not allow children or pets to drink from natural bodies of water.
• Keep children and pets out of the areas experiencing a harmful algae bloom and quickly wash them off with fresh water after coming into contact with algae.
• If you or your animals experience symptoms after swimming in or near an algal bloom, seek medical/veterinarian care.
• If you suspect you experienced health-related effects following exposure to a bloom, contact the Virginia Harmful Algal Bloom Hotline at 888-238-6154.
• To learn more about harmful algae blooms, visit SwimHealthyVa.com.