WORCESTER, Mass. - Indian Lake remains closed due to elevated levels of cyanobacteria.

The city's Department of Inspectional Services closed the lake after finding high levels of cyanobacteria, which can be harmful to people and pets.

A Clark University professor says dogs who swim in water containing the blue-green algae could suffer serious, and even fatal, health conditions.

Dr. Nathan Ahlgren says in humans the toxic compounds can damage the liver, cause a rash or blisters on the skin, and potentially even cause severe neurological problems.

“A lot of urban lakes have a lot of nutrient inputs. High temperatures tend to favor cyanobacteria, these toxic varieties,” Dr. Ahlgren said. “Also nutrient input because the growth of the cyanobacteria and indian lake often has a combination of those two things."

Ahlgren says the city does a good job of maintaining the algae. He says there is also a Citizen Science program, run by a Clark alum, who monitors pond health and cyanobacteria across multiple ponds.