78 
Hunt - Operational experience worldwide 
weathering of the oil and its movement towards sensitive resources. To avoid delays at the 
time of a spill, the decision on whether dispersants can be used and if so, the precise cir 
cumstances under which they may be used, need to be agreed during the process of devel 
oping contingency arrangements for spill response. 
Concluding Remarks 
Dispersant use at oil spills can be a controversial topic, at times generating widespread de 
bate in the media and public forums, particularly during the aftermath of the DEEPWATER 
HORIZON spill. Their use can be seen as adding another unwanted pollutant into the envi 
ronment that may prove toxic to marine fauna and flora. In addition, it is recognised that dis 
persant application is not appropriate for some spill scenarios, depending on oil type, sea 
state and the proximity of resources that would be particularly vulnerable and sensitive to 
dispersed oil. However, from ITOPF’s perspective there are considerable advantages to hav 
ing dispersants as an available option to responders, albeit on the basis of a thorough Net 
Environmental Benefit Analysis (NEBA). In our view, the complete dismissal of dispersants at 
the contingency planning stage strips those charged with responding to spills of one of their 
most powerful tools, and thus limits their capability in situations when containment and re 
covery is likely to be highly ineffective or potentially unfeasible. 
Operational experience has shown that mechanical recovery of oil at sea is severely ham 
pered by strong currents and rough seas, and can be rendered unfeasible if conditions are 
particularly inclement, or if the equipment and/or expertise are insufficient. In ITOPF’s expe 
rience, it is rare for containment and recovery operations to collect more than around 10- 
15% of the spilled oil, even in the most favourable of conditions. Bearing this scenario in 
mind, it is also important to recognise that in many cases a large proportion of the oil that has 
not been recovered at sea will eventually drift ashore, sometimes in the form of a highly per 
sistent water-in-oil emulsion, which can be more than three times the original volume spilled 
at sea. However, if the spilled oil is amenable to dispersion, and the circumstances are ap 
propriate, a well-timed and suitably-scaled dispersant spraying operation may considerably 
reduce the extent and severity of damage to sensitive coastal resources, as was found dur 
ing the response to the SEA EMPRESS spill. 
There is also merit in recognising that in contrast with containment and recovery operations, 
dispersant application is typically more effective in choppy sea conditions, such as those 
which typify the North Sea. Indeed, the process fundamentally requires a certain degree of 
wave action, and when formulating a spill response strategy it is worthwhile considering that 
dispersants simply act to enhance the natural dispersion of oil. Provided that the oil is ame 
nable to dispersion and the energy is sufficient, dispersed oil will be present to varying de 
grees in the water column even before dispersants are applied. Therefore, in such circum 
stances the decision on dispersant use may not necessarily be a case of deciding whether it 
is acceptable for oil to enter the water column, since such a scenario may be inevitable, as 
was seen during the TASMAN SPIRIT spill. In such situations, it may be more realistic to 
think of the decision to spray as relating to the acceptance and promotion of this natural pro 
cess. 
For many of the reasons outlined above, we suggest that there is considerable merit in giving 
appropriate thought to the role that dispersants might play in different spill response scenari 
os during the contingency planning process. While dispersants are not the panacea of oil 
spill response, having a number of key limitations in some situations, it should be recognised 
that there is no cure-all solution for dealing with spills, with all strategies having positive and 
negative implications. In the appropriate circumstances dispersants have been shown to be 
highly effective at reducing the environmental and economic impacts of oil spills, although 
there is a need for a rapid response due to the typically short window of opportunity. If a clear 
dispersant policy exists, with pre-approved areas for application drawn out on sensitivity