Shipping vessels can produce a lot of toxic material at sea, from exhaust and from the paint of the hull for instance. Thus, Hideo Okamura works on TBT substitutes and antifouling biocides from the maritime environmental management perspective, he also investigates the ecotoxicological impacts of ship diesel exhaust particulates on marine environments. This two main vectors contribute to his broader research interests in ecotoxicity assessment of natural environments by biomonitoring.