At least 3 lines. Biggest one is probably CMA-CGM (taking pax is a policy of the company's founder and there's no security- screw 9/11 and all that security cr@p) with some 75 ships that take passengers (grand total of <1,000 pax a year). Other lines that do include Hanjin and Hamburg Sued.

See the thread about trans-oceanic crossing a page or two back.