I watched a TV documentary  about ship freight last week called" Freightened". Apparently ships use absolutely filthy fuel that out matches the emissions from cars but has not caught the attention of global emission standard limits. The flags of convenience used by most of these ships allow them to avoid domestic laws such as labor standards and maintenance schedules and the location of the beneficial owners is often impossible in the case of disasters such as sinking or spills so Joe taxpayer pays to clean up. Many shipping companies are located in tax havens so avoid tax as well. Time for governments to get together and clean up this industry .Many of the ships, especially those carrying oil/bunker oil are in terrible shape and threaten the environment.