Response continues to mineral oil spill in Straits of Mackinac

Straits of Mackinac during a Coast Guard Air Station Traverse City MH-60 overflight on April 4, 2018. The Coast Guard conducted overflights of areas of interest for a mineral oil spill from a submerged utility line to monitor the extent of the spill and identify any product on the surface. (U.S. Coast Guard photo).

Straits of Mackinac during a Coast Guard Air Station Traverse City MH-60 Jayhawk helicopter overflight on April 4, 2018.  (U.S. Coast Guard photo).

MACKINAW CITY, Mich. — The Unified Command has isolated the impacted utility lines and is monitoring the removal progress of the remaining mineral oil from those lines, Thursday.

The Oil Spill Response Organization, contracted by the American Transmission Company, removed approximately 10 percent of the mineral oil from one of the utility lines yesterday. The Unified Command will continue to consult with oil recovery experts and engineers today to ensure the oil extraction process is effective.

Approximately 400 gallons of oil remains in each utility line and is not known to be leaking from the source. The estimate that 600 gallons of mineral oil leaked from the utility lines before securing the source remains unchanged.

The Coast Guard deployed an MH-60 Jayhawk helicopter crew from Coast Guard Air Station Traverse City on Monday and Wednesday afternoon to search for pollution over the Straits of Mackinac. The flight crews used infra-red technology to detect temperature differences between the oil and water and did not locate any oil sheen or signs of pollution. Coast Guard overflights will continue to monitor the spill.

“DEQ continues to work within the Unified Command established to address this situation,” said Scott Schaefer, DEQ Incident Management Specialist. “We are working with the American Transmission Company and our federal, tribal and local partners to address the release of mineral oil to the Straits of Mackinac.”

In consultation with engineers from the Pipeline and Hazardous Materials Safety Administration and the Michigan Department of Environmental Quality, a 10-person work crew and vacuum truck are on site for the OSRO working to draw the oil out of the two decommissioned utility lines; no pressure is being applied to the lines. A suction, or negative pressure, is present on the entire span of the lines across the Straits.

The calculated trajectory of the spilled mineral oil is to the south and southwest of the source. Given the dilution of the product and the mobility of fish, there continues to be a low risk to fisheries and wildlife. A concern remains that waterfowl or shore birds may come in contact with the product floating on the surface. The Unified Command is exploring methods to deter birds from the area.

Due to the inaccessibility of the shorelines from ice, the threat to the public is low since they are unable to come in contact with the oil. The dilution of the oil and distance from the bridge and water intakes provide additional protection from the product.

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