On our way back into the Port of Portland we saw 2 extremely large ships and were told they are crude oil tankers. The Port of Portland is the largest oil port on the east coast. The two tankers docked there on this day were foreign tankers but the oil could have come from anywhere. The oil brought to Portland is piped through a pipeline to Canada. It takes several days to pump the oil out of the tanker and precautions are taken against oil spills while the ships are docked.