After decades of prohibiting trucks from legally transporting hazardous materials over the Ambassador Bridge that carries traffic between the U.S. and Canada, Michigan has proposed lifting the ban.

The state transportation department is accepting comments on the idea until May 27, though it could be many months or a year before the restriction is possibly repealed.

The Detroit News reports the ball got rolling in 2008 when the owner of the Ambassador Bridge, the Detroit International Bridge Co., requested the Michigan DOT review the ban. Last December the department released a study supporting the idea of allowing hazardous material cargo across the bridge, except for explosives and radioactive materials.

Currently trucks needing to haul hazmat between Michigan and Winsdor, Ontario, across the Detroit River, must use the Detroit-Windsor Truck Ferry service. Hazardous materials are allowed across the Blue Water Bridge between Port Huron and Sarnia, Canada, but are restricted to designated lanes.

A second crossing between Detroit and Windsor, being built with Canadian assistance and will compete for traffic with the Ambassador Bridge, reportedly will allow hazmat truck shipments.

The issue has raised concerns on both sides of the U.S.-Canadian border including from Windsor officials, who are concerned the Michigan DOT has not studied the issue thoroughly. There is opposition from the owner of the truck ferry service and some Michigan lawmakers.

A spokesman for the Michigan DOT says the issue is “not a done deal” and any change will be in consultation with the motor carrier division of the Michigan State Police.