The 1991 Gulf War in Kuwait resulted in one of the largest marine environmental pollution incidents in history. It comprised a marine oil spill and emission of burnt and unburnt crude oil from the oilfields. Survey results, including those obtained during the 100-day Mt Mitchell cruise, showed that overall damage to the subtidal marine ecosystem was less than initially expected since: 1. the spilled oil moved relatively rapidly to the south and became stranded on the Saudi Arabian coast causing significant damage to the intertidal zone; 2 between the time of the invasion of Kuwait, 1 August 1990 and the present time (1993) chronic discharges have stopped or become significantly reduced due to reduction in oil industry and transport in both Kuwait and Iraq; 3. the Gulf marine ecosystem is acclimated to oil pollution and capable of assimilating even high petroleum inputs because (a) the microbiological population has been exposed regularly to oil pollution from natural seepage, (b) oil degradation and transformation rate is high due to the high temperature, and (c) photo-oxidation of polyaromatic petroleum compounds is significant due to the strong solar radiation intensity. Most surveys have focused on petroleum-related primary polluting compounds including certain heavy metals. However, the Gulf environment, particularly in Kuwait, could have been exposed to other hazardous materials, such as PCBs from destroyed transformers, used catalysts from damaged disposal sites and different war materials such as bullets and shell fragments. Also significant are secondary polluting compounds, which are produced as breakdown, conversion products during environmental weathering of petroleum. Among these compounds oxidation products may have surface-active properties and can help the dispersion of the hydrophobic petroleum residues. These may also be complexing agents and enhancing mobilization of inactive pollutants such as heavy metals accumulated in sediments. There is a potential for long-term input into the marine environment from the Kuwaiti desert, where several million tons of petroleum-related deposits create crusts during environmental weathering. These could become broken down into small, tar ball type particles and could be transported to marine areas by wind and dust storms. It is important that future survey and assessment programmes are designed to take into account all of these considerations.