old, Tired and Rusty
Metals need the help of man. Unless cared for properly, they can become surprisingly fragile. This lesson was driven home in 1998 by three disturbing incidents: A 50-year-old oil tank popped like a balloon, spilling three quarters of a million gallons of diesel fuel into a river that supplies thousands of people with water. A 19-year-old airliner shed part of its fuselage at 24,000 feet, catapulting a flight attendant to her death and injuring 61 other people before making a miraculous landing. And an 85-year-old bridge, a major artery into a major city, was closed for six weeks because authorities feared that year of neglect had brought it to the brink of collapse....
Half a century into its industrial ascendancy, the United States is littered with old oil tanks, airplanes, bridges, and other metal structures, They are all subject to decay. They have to be inspected frequently, and they have to be maintained. Otherwise they break.