By JOHN FLESHER, AP Environmental Writer

TRAVERSE CITY, Mich. (AP) — Michigan Gov. Rick Snyder and Canadian oil transport company Enbridge Inc. announced an agreement Monday intended to boost the safety of twin oil pipelines beneath the waterway where Lakes Michigan and Huron converge.

The deal does not call for the decommissioning of Line 5 as environmental groups have demanded, although it does include a procedure for temporarily halting the flow of oil through the 5-mile-long (8-kilometer-long) underwater segment when storms cause sustained periods of high waves.

It also calls for a study to examine the possibility of digging a tunnel beneath the Straits of Mackinac through which the existing pipelines — or a new one — could be routed. The two 20-inch (50-centimeter) lines have lain on the lakebed since 1953.

It also calls for steps to allow faster detection of and quicker response to a potential spill.

“Business as usual by Enbridge is not acceptable and we are going to ensure the highest level of environmental safety standards are implemented to protect one of Michigan’s most valuable natural resources,” Snyder said.

Line 5 is a 645-mile (1,040-kilometer) line that runs from Superior, Wisconsin, through northern Michigan to Sarnia, Ontario.

The company says the 5-mile (8-kilometer) underwater segment is safe, but environmental groups and some officials have raised concerns about recent disclosures of gaps in protective enamel coating.