I'm excerpting from FMC Commissioner from a speech he gave a few years ago. He gives reference to some of the history behind the anti-trust exemptions..
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http://www.fmc.gov/speeches/newsrelease.asp?SPEECH_ID=44
In the most expansive version of my standard speech about the Ocean Shipping Reform Act of 1998, I trace the history
of the ocean carrier antitrust immunity all the way back to Alexander Committee investigation of 1913
Ocean carriers engaged in the United States international trade have been regulated since the early part of the last century. In 1994, Congress began to seriously consider revisions to the most recent version of the law providing for the oversight and regulation of international ocean liner shipping -- the Shipping Act of 1984. Following four years of review and deliberation, Congress passed and the President signed the Ocean Shipping Reform Act of 1998.
The Ocean Shipping Reform Act is not a total deregulation of the ocean transportation system. Congress preserved and reaffirmed the antitrust immunity for ocean carriers and retained some elements of tariff publication and the common carriage system
Thanks for the clarification!