Ballast water may contain toxins, invasive plants, animals, viruses, and bacteria.
==== Jurisidictional problems =====
Overlapping jurisdictions may pass legislation which creates conflict of laws. For interest, recent changes in California law intended to reduce air quality problems from shipping has been interfered with by Federal legal changes intended to reduce the cost of shipping. <ref> www.santabarbaraindependent.com|July 2, 2011</ref>