Okay. It's good to know there's a limit to how high, but they are very high, as we've seen in the pictures.
Are there also some rules like those for freight trains? When you put together a freight train, you can't put combustible material too close to the engine. Do some rules to that effect exist?
Are those same rules in effect when they are stacking containers on a ship? Do they have rules that would put the most dangerous cargo lower down and therefore least likely to be lost overboard?