As piles of black petroleum coke grow and multiply across the Detroit River, so do concerns in Windsor.

People protested in Windsor on the weekend, across from the four-story high piles of oil refinery by-product.

Dozens of people gathered in Assumption Park to speak out.

Windsor West NDP MP Brian Masse was one of those who took a turn at the microphone.

"To have this there is obviously wrong in that environment. We've de-industrialized the waterfront over a number of decades, with massive investment and more investment to come because we want to return the river to a natural-heritage type of a place, where it's going to be a producer of a good place to live," he said.

Masse is concerned the petroleum product will threaten the water and air.

He's asking the federal government to have the International Joint Commission step in.

Doug Hayes, of the local chapter of the Council of Canadians, is also concerned.

"This will be blowing right into our environment," he said. "If it has ... contaminants in it. We're breathing all those contaminates and our health is at risk."

Petroleum coke is a by-product of refining oil and can be burned as an energy source.

Pat Noonan, with Windsor on Watch, wants something to be done soon. 

"Whenever they investigate environmental problems it goes on and on for years," Noonan said. "We haven't got any time to waste."