For those living in the Great Lakes region of the U.S., a warning re-issued in Michigan this week may provide a shuddering thought: authorities there say they are unprepared to deal with a heavy crude spill in the lakes.

Speaking Tuesday at the Detroit/Wayne County Port Authority at an international forum on "sinking oils, known as Class V" (which includes tar sands), Rear Adm. Fred Midgette, commander of the U.S. Coast Guard's District 9, said that responders, including the Coast Guard, were urgently trying to come up with a plan to deal with a potential heavy spill in Great Lakes' waters, the Detroit Free Press reports.

The Free Press adds:

Midgette said he was particularly concerned that response plans and organizations "are not capable of responding to heavy oil spills, particularly in open-water scenarios," in an Aug. 20 memo to the Coast Guard's Deputy Commandant for Operations.

On Wednesday at the Great Lakes Restoration Conference in Grand Rapids, Jerry Popiel, incident management advisor for the U.S. Coast Guard’s Ninth District, made a similar warning about the potential of heavy crude traveling across the Great Lakes. “The piece we really struggle with is the recovery of heavy oils off the bottom in deep water,” MLive.com reports him as saying.

Lyman Welch, a water quality program director with the Alliance for the Great Lakes, who spoke along with Popiel, said, “Look at the Kalamazoo example and what happened there,” referring to the 2010 spill of tar sands crude from an Enbridge pipeline.

The Coast Guard outlined these problems in a 2013 report, stating in its Executive Summary: "Current methods are inadequate to find and recover submerged [class V] oils with responders having to reinvent the techniques on each occasion."

The Alliance for the Great Lakes issued a report last year as well which focused on the region's gaps in preparedness for tar sands spills. “The regulatory and response framework for petroleum shipping on the Great Lakes is not fully up to the task of protecting the lakes from spills today, and is certainly not an adequate starting point from which to consider the viability of tar sands crude shipment by vessel,” the report stated.

These reiterated warnings come as Calumet Specialty Products Partners L.P. weighs shipping tar sands crude across the Great Lakes.

“We are only seeing the tip of the iceberg and only just beginning to understand the grave impacts these extreme energy projects are going to have on the Great Lakes," Maude Barlow, chairperson of watchdog group Council of Canadians, warned earlier this year. "If governments continue to allow projects like this, what are our lakes going to look like in 20 or 50 years?” she asked.