WASHINGTON – Northwestern Lake Huron can be fickle and treacherous, with at least 45 Great Lakes-plying ships succumbing over the years to its gales, fog and rocky shoals. There's an 1844 side-wheel steamer in the water, and a modern 500-foot German freighter.

This so-called Shipwreck Alley delights divers and feeds a tourism industry with glass-bottom boat rides in the 448-square-mile Thunder Bay National Marine Sanctuary off Alpena, Mich. And now, 13 years after its creation, the federal government wants to expand that sanctuary ten-fold, to cover 4,300 square miles and protect at least 47 more shipwrecks.

But unless changed, the expansion plans – hugely popular in the towns of northeastern Michigan, to judge from letters of support -- could choke off shipping of the iron ore and limestone used to make steel and other products in cities like Cleveland. That, at least, is what maritime interests such as the Lake Carriers' Association, based in Rocky River, Ohio, say.

"It is no exaggeration to say that if iron ore could not move in ships, America's steel industry would fade into a mere shadow of its former self," James Weakley, president of the Lake Carriers' Association, said in a 17-page letter of concern to the federal government last week.

The proposed expanded sanctuary covers "some of the most heavily trafficked shipping lanes on the Great Lakes," he said. Vessels that have loaded iron ore from ports on Lake Superior "must transit the Sanctuary when bound for steel mills in Indiana, Michigan, Ohio, Pennsylvania and Ontario," he said.

Just restricting shipping around the expanded sanctuary itself could put three major Michigan ports – Alpena, Calcite and Presque Isle – off limits, the association says, and rob other Great Lakes ports of the materials that fuel Midwest industries.

That never appeared to be the intent.

Supporters of expanding the sanctuary, one of only 13 national marine sanctuaries nationwide, say they just want to make a rich historical and cultural asset better.

"It's a heritage issue for us," said Marie Twite, supervisor of the Alpena Township trustees, whose community was part of the original preserve and who backs the expansion. "It's part of the shipping of the Great Lakes and what happened with the vessels and how that all impacted us. We are very interested in preserving that and letting people come out and experience it."

Technically, nothing in the expansion proposal by the National Oceanic and Atmospheric Administration, or NOAA, would pose specific barriers to currently navigable waters. NOAA does not say it wants to restrict Great Lakes shipping. If anything, it wants more people visiting the water and protecting its treasures from scavengers' plunder.

But under a matrix of federal rules, the Coast Guard polices NOAA sanctuaries. That means the Coast Guard must enforce numerous regulations, including those promulgated by the Environmental Protection Agency under the Clean Water Act and incorporated into Coast Guard rules.

And those rules, say shipping and industry interests, restrict ships from anchoring or taking on or discharging ballast water in federal marine sanctuaries.

Ships add or discharge ballast water to distribute weight as they prepare to load or offload cargo. They use ballast to better maneuver, and to gain stability when they fear foul weather. But discharging ballast has potential to harm sensitive marine life and coral, as does anchoring, which is why both are generally prohibited in marine sanctuaries.

One big difference between most marine sanctuaries and the one on Lake Huron: The latter was created in 2000 to protect sunken ships, not coral reefs. Ballast operations would make no difference to a sunken ship, Weakley said in a telephone interview.

"It makes absolutely no sense if the resource you're trying to protect is a sunken vessel," he said.

Kevin Whyte, vice president and general counsel for Carmeuse Lime & Stone, which extracts limestone in Rogers City, Mich., and ships it throughout the Great Lakes, told NOAA in a letter that if ballasting is prohibited, "it could be a serious safety concern for the vessels entering and exiting the port during high-wind events, which are quite common in Northern Michigan throughout the shipping season."

It could even result in more shipwrecks, said Weakley.

Shippers could "end up in a situation where our vessels cannot safely operate in the area that's known as the crossroads of the Great Lakes," he said in an interview. "And you have to appreciate the irony that the marine sanctuary, which is designed to protect sunken vessels, is creating the potential of more sunken vessels by encouraging vessels that operate there to operate in an unsafe manner."

That's why he hopes NOAA will carve out a shipping exemption if it expands the Thunder Bay sanctuary. It has done so once before, in the Gray's Reef National Sanctuary off the coast of Georgia, he said.

The Lake Carriers' Association says it supports expanding the Great Lakes Sanctuary. It just wants ongoing shipping interests protected. Congress members from Michigan, including Sens. Carl Levin and Debbie Stabenow, appear to support such a balance, as does Michigan Gov. Rick Snyder.

Snyder wrote to NOAA last month enthusiastically supporting the expansion, but he added that "an adverse affect on businesses that utilize docking facilities to move products would be an unintended consequence of boundary expansion that must be avoided."

NOAA, the Coast Guard and the EPA were unavailable for comment. All but their essential operations are shut down due to lack of congressional funding.

NOAA's public comment period for the expansion runs through Oct. 18. For now, the shippers say that despite their worries, they are optimistic the sanctuary will be expanded without curtailing commercial maritime operations.

"At least at the Congressional level everyone appears to be on the same page with us: celebrate the region's maritime industry while allowing it to continue to operate safely," Weakley told The Plain Dealer in an email. "So it appears that everyone is trying to get to the same place and it is a matter of the regulatory agencies getting there."

"I don't think," said Whyte, of Carmeuse Lime & Stone, "that we are at all opposed to the expansion of the sanctuary. We just want to make sure that this would continue the normal vessel operations, and we don't really think that the normal commercial vessel operations have a negative impact on the sanctuary, whether it's releasing ballast water or regular shipping."

After all, said Weakley, the expanded sanctuary could indirectly benefit the shipping industry and its vessels. That is, he said, it "celebrates our industry and our heritage."