DETROIT, MI – The petroleum coke piles that have amassed along the Detroit River in recent months are now dwindling, a spokesman for the company that stores them said, and should be gone by fall, but that does not mean they cannot or will not return.

And U.S. Rep. Gary Peters (D - Bloomfield Township) told a community roundtable Tuesday that the growing local concern should now expand its focus beyond the banks of the Detroit River.

Koch Carbon is shipping the large black mounds of tar sands byproduct to a site in Ohio, and Peters said the storage of petroleum coke has now expanded to cities across the country.

“Pet coke must be stored properly whether it’s here in Michigan or wherever these piles are being moved in the Great Lakes region,” Peters said. “Your efforts as small business owners, neighbors, and the community at large to raise concerns over the pet coke’s impact on public health and safety cannot stop now.”

Detroit Bulk Storage, the company responsible for storing the petroleum coke, is currently going through a permitting process with the city and the state Department of Environmental Quality.

Company spokesman Daniel Cherrin said the permitting process will address a “dust mitigation plan,” but that does not necessarily mean the piles will have to be stored in a closed facility, as some politicians and environmentalists have asked for.

“It is common industry practice, particularly on the Great Lakes, to store petroleum coke and other products out in the open , and they are covered with an epoxy,” Cherrin told MLive Tuesday.

That epoxy sealant on Detroit Bulk Storage's petroleum coke was apparently broken on a windy day last month while the piles we're being moved onto boats, prompting residents in Windsor, Ontario to shoot footage of black dust from the piles blowing across the Detroit River (video below).

The video was seized upon by Peters, who called it “firsthand evidence” that blow-off from the piles is not being contained.

Cherrin said Detroit Bulk Storage is not taking any more shipments of petroleum coke as it goes through the permitting process, but did not rule out storing it in the future.

He also said that Detroit Bulk Storage wants to participate in community discussions on petroleum coke storage but has yet to be invited to do so.

"The congressman has not reached out to Detroit Bulk Storage, we were not invited to this roundtable discussion. Detroit Bulk Storage wants to be part of this discussion," Cherrin said, adding, "We want to be responsive to the community’s concerns."

The petroleum coke was produced by Marathon Petroleum refinery but is owned by Koch Carbon, which is run by well-known businessmen Charles and David Koch.

Marathon has been refining Canada's growing exports of oil sands from Alberta and selling the waste product to Koch since November, according to the The New York Times, which said in a report that Canada plans to increase tar sands exports to the United States via the proposed Keystone XL pipeline.

The state Department of Environmental Quality has concluded that the black mounds do not pose an immediate health risk. The MDEQ has said the piles are compliant with regulations, and Detroit bulk Storage has maintained that they are being properly stored.

Petroleum coke can be burned with coal for a cheaper, though dirtier, form of energy. Because of stricter standards by the EPA in the U.S., much of the oil sands byproduct is expected to be exported to Far East countries such as China.