Sewage discharged into the Niagara River

"Niagara Falls and the Niagara River are a world-class destination for tourists and we should not be polluting this unparalleled natural resource", Cuomo said via a statement.

While the black water may have startled some visitors, Niagara Falls Water Board executive director Rolfe Porter told WGRZ it's a routine procedure and "there shouldn't be any concerns about health".

A patch of black drifting through the waters of the lower Niagara River on Saturday was a result of "routine maintenance" by the Niagara Falls Water Board.

Officials say there were some accumulated solids and carbon residue in the water, which is what caused the inky color.

Video tweeted from the Maid of the Mist Twitter account shows dark water surrounding the boat launch site below the falls.

The water near the base of Niagara Falls turned an alarming shade of black before tourists' eyes following a foul-smelling discharge from a wastewater treatment plant.

Among the first to notice the problem was Pat Proctor, vice president of Rainbow Air Inc, which provides helicopter tours over the falls.

Wastewater flows through carbon beds as part of a seven-step purification process, according to the water board's website. The spokesman, Kevin Keenan, referred other questions to the city and state.

The New York State Department of Environmental Conservation says it is investigating, while the Niagara Parks Commission says it is following up to assess the impact on the environment.

It took several hours before the smell and discharge dissipated.

Vanessa Coleman