The Minnesota Pollution Control Agency has reportedly identified potentially harmful toxins in the algal blooms found at Beaver Lake in Ellendale last week.

The results announced Thursday were reportedly found after examining recent water samples from the lake, which has been closed since Saturday morning because of a severe algal bloom that was first reported as a sewage spill.

The agency stated the toxin detected in the water must be swallowed to be harmful, according to a news release. In extreme cases, dogs and other animals have reportedly died after drinking lake water containing the toxins.

“If noticing a severe algal bloom in the water or scum on shore, people should avoid contact with the water and prevent their pets from swimming or drinking the water,” the release stated.

People should look for sludge or other matter on the water surface and shoreland. Though harmful algae is often described as looking like pea soup or spilled green paint, it can take other forms as well. It can also be hard to distinguish from other forms of algae.

Scientists do not yet know what causes some algal blooms to produce toxins, while others do not.

According to the release, there are no short-term solutions to fix a blue-green algal bloom. Once the bloom occurs, the only option is to wait for the weather to change to disrupt the algae’s growth.

The agency stated the bloom is reportedly unusual for Beaver Lake, which was one of five lakes that fully met water quality standards for fishability and swimability in a recent study that looked at 45 lakes in the Cannon River Watershed District. The lake is 27 feet at its deepest and is popular for recreation.

The Beaver Lake shelter, playground and restroom facilities were expected to open Wednesday. The beach, however, was planned to remain closed pending official lab results.

MPCA officials stated the key to solving algae problems long-term is to improve water quality by decreasing the amount of nutrients that runoff carries into lakes. They encourage buffers along ditches and shoreland, including cabins on lakes, manure management, fertilizer management on crops and lawns, controlled cropland drainage, planting cover crops and sewer system upgrades and maintenance.