Tourists to Niagara Falls on the weekend were greeted with black smelly water in the lower Niagara River on Saturday.
The incident was made public by a video tweeted out from the Maid of the Mist boats on the American side showing dark water surrounding the boat launch area.
A statement released by the Niagara Falls New York Water Board said it was the result of routine maintenance that saw waste water dumped into the river.
The board also apologized for causing alarm to residents, tourists and others.
The U-S Department of Environmental Conservation is still investigating the incident.