In the East Boston tunnel , a worker on April 10, 1932 ties in the reinforcing rods of the curved ceiling that will be buried in the concrete.  Reports of the concreting of the tunnel at the time said that the level of safety was such that if the outside coating of cement between the steel and the mud were to wear away and if the steel itself were to corrode to nothing, this inside 18-inch wall of concrete would still stand and make a safe tunnel.