The Michigan Department of Environmental Quality has rejected a company's request to store piles of petroleum coke at an open riverfront site in Detroit.

In a letter Thursday to Detroit Bulk Storage, Lynn Fiedler of the department's air quality division says the company failed to outline sufficient dust control measures, even in a revised version of its application.

  Detroit's mayor last year ordered the company to remove piles of the waste product from a site along the Detroit River near the Ambassador Bridge.

 Petroleum coke is burned as fuel in cement kilns and power plants. The piles in Detroit were from Marathon Petroleum Corp.'s refining exports from oil sands in Alberta, Canada.

An attorney for Detroit Bulk Storage says the company respects the department's decision and will review its options.