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pability and revise their national contingency plan. The outcomes of such reviews can pro 
vide useful information on the benefits and limitations of dispersant application in those par 
ticular scenarios. 
Fortunately, major oil spills are relatively rare. Certainly in modern times. But this also means 
that the number of cases where large-scale dispersant operations have been carried out, and 
where detailed information is available, is also rather limited. In addition, it’s worth noting that 
dispersant application was not considered to be an appropriate strategy in response to many 
major spills due to factors such as oil type (e.g. Heavy Fuel Oil), weather conditions (e.g. too 
much or too little wind), location (e.g. too close to shore and/or too shallow) or as a result of a 
national response policy that does not favour this approach. For example, dispersants were 
not applied during the response to the AMOCO CADIZ incident (France 1978) as a result of 
the proximity to shore. Dispersant application did not play a key role during the response to 
the EXXON VALDEZ spill (USA 1989), although they were used to some degree. In addition, 
they were not applied during the response to the ERIKA (France 1999) and PRESTIGE 
(Spain 2002) incidents due to the highly viscous nature of the oil spilled in these cases. 
Looking back over the past ten years of ITOPF records (2005-2015), of the 222 incidents for 
which our technical team has attended on site, there were seven major crude oil spills 
(>700 MT), and just two of these incidents resulted in the confirmed use of dispersants. 
Hence, it is clear that large-scale dispersant operations to ship-sourced spills occur relatively 
rarely. However, it is also notable that two major dispersant spraying operations have been 
carried out in response to offshore blowout incidents in recent years: namely the MONTARA 
incident in the Timor Sea in September 2009, and the DEEPWATER HORIZON incident in 
the Gulf of Mexico in April 2010. The latter incident is widely regarded as the largest acci 
dental oil spill in history with an estimated 4.9 million barrels of crude oil released from the 
well (source: US EPA). The response involved the largest scale use of dispersants for any 
spill, with some 1.8 million gallons (6.8 million litres) applied to the released oil (source: US 
EPA). Approximately 40 % of the dispersants used in the response were applied directly at 
the source, some 1,500 m below the sea surface, with the remainder applied in the conven 
tional way by spraying onto surface slicks, using both aerial platforms and vessels. 
It is understood by ITOPF that for the purposes of this risk assessment process for spills in 
German waters, the focus is on the potential for dispersant application in response to ship- 
sourced spills, and hence the case studies discussed in this report relate to such incidents. 
Case Study: SEA EMPRESS (United Kingdom 1996) 
Despite the fact that we are approaching the 20 th anniversary of the SEA EMPRESS oil spill, 
this case is still a highly pertinent one when it comes to the subject of operational experience 
of dispersants. Prior to the DEEPWATER HORIZON blowout, the response to the SEA EM 
PRESS involved the largest scale application of modern concentrate (Type III) dispersants, 
and as a result there are some key lessons that can be learned from this incident. 
The oil tanker SEA EMPRESS, carrying 130,000 tonnes of Forties Blend crude oil from the 
North Sea, ran aground in the entrance to Milford Haven in Pembrokeshire, South-West 
Wales on the evening of 15 th February 1996. Although the tanker was re-floated within a 
couple of hours, she sustained serious damage to her starboard and centre tanks, resulting 
in a large-scale release of oil. Attempts to bring the vessel under control and to undertake a 
ship-to-ship transfer operation were thwarted by severe weather and the tanker grounded 
and re-floated several more times over a period of five days. In all, some 72,000 tonnes of 
crude oil and 370 tonnes of heavy fuel oil were released into the sea between the initial 
grounding and the final re-floating operation.