BOSTON (AP) — Massachusetts transportation officials are closing the southbound side of the Tobin Bridge, U.S. Route 1, into Boston because of the possibility of construction materials blowing on the road.

The state Department of Transportation said Monday evening that tarps securing a construction site on that upper part of the bridge have come loose in high wind and workers cannot safely secure the materials until the wind subsides.

The outbound lower level of the bridge, the northbound section, remains open.

The DOT says it’s expected the inbound bridge will reopen at least by the Tuesday morning commute.

Copyright 2012 The Associated Press.