Support growing for new super lock at Sault.

The failure of a navigation lock at Sault Ste. Marie, Mich., last summer has an American industry group and politicians clambering for Washington to get moving on building a second super-sized lock.

In its annual report, the Great Lakes Maritime Task Force, a labour-management coalition, warned that the 20-day closure to make repairs to the MacArthur Lock in 2015 highlights the need to address a critical chokepoint on the St. Lawrence Seaway.

The group said the lock's breakdown provided an uninviting preview of the consequences to shipping and American industry should its larger sister lock, the Poe, ever be disabled for a period of time.

Repairs to the MacArthur Lock delayed nearly two million tons of cargo aboard U.S.-flagged vessels from reaching port on time. Damage to the Poe would cancel shipments, as only the largest lake freighters can use it to transit from Lake Superior to the lower lakes. About 70 per cent of the American fleet would be halted, and steel mills in Indiana, Michigan and Pennsylvania would face critical shortages of iron ore.

"A lengthy closure of the Poe Lock would slow trade to a trickle at

best," said the group in its report.

There are four commercial locks at the Sault, of which two have been retired for decades by the U.S. Army Corps of Engineers, leaving only two remaining for shipping.

Michigan Gov. Rick Snyder also called for twinning the Poe Lock in his January 2016 State of the State address.

Similar sentiments were echoed by the Ohio House of Representatives in recently passing a resolution urging the White House and the U.S. Office of Management and Budget to back...