Morses Pond neighbors this week have been wondering why the water in the pond has been turning purple, and they’ve now found their answer: potassium permanganate

The town’s Department of Public Works discovered the source of the purple water is a company in Natick doing disinfection near the Cochituate aqueduct behind an industrial park.

The good news is potassium permanganate is safe; Wellesley uses it to treat its drinking water, though filters the purple out before water gets to residents.

Nevertheless, the state Department of Environmental Protection is investigating how the material go into the aqueduct.