As weather warms, DHEC cautions citizens on potential dangers of algal blooms

April 18, 2022

As swimmers and boaters begin to enjoy the warmer weather on South Carolina’s lakes and rivers, the South Carolina Department of Health and Environmental Control (DHEC) cautions citizens to be aware of potentially harmful algal blooms in the surface waters of natural, untreated rivers and lakes.

Algae and cyanobacteria are tiny plant-like organisms that, under the right conditions can overgrow in rivers, lakes, and oceans. This rapid growth can be associated with foam, scum or thick layers of algae on the surface of water.

Algal blooms can look and smell bad and may cause the water to appear green, red brown, or blue in color. Some algal blooms are formed by species that can produce toxins. When they contain toxins that affect the health of people, animals and the environment, they are known as harmful algal blooms (HABs).

“If you’re planning on recreating in a water body, we advise you to visually inspect the water before going in,” said Emily Bores, DHEC’s HAB Coordinator. “If you notice a foul smell or discoloration, it’s best to err on the side of caution and stay away. Remember, when in doubt, stay out.”

HABs are more likely to occur in late spring to early fall when water temperatures are warmer and there is increased sunlight. You cannot tell whether or not a bloom is harmful just by looking at it, so if an algal bloom is suspected, keep yourself, others and pets away from the area. To notify DHEC of a bloom in the state’s lakes, rivers, streams or estuaries, contact the HAB hotline at 803-898-8374 or email the HAB Coordinator at [email protected].

For the most up to date information on HABs occurring in South Carolina, please go to or visit the HABs app at

If you or your pets encounter water that possibly contain a HAB, immediately rinse with tap water and do not allow pets to lick themselves before they’re rinsed off. Seek immediate medical attention if illness occurs.