Dispersant use can be a critical component of an effective response to larger offshore oil spills. When used appropriately, dispersants can reduce the potential for long term environmental damage by preventing oil slicks from entering sensitive near shore environments or stranding on shorelines. Preparedness is essential for successful dispersant application – product selection and inventory management are critical elements for ensuring global dispersant stockpiles are response ready.
Product Selection: A number of factors need to be carefully considered while selecting specific dispersants, especially in the case of large scale response-related inventories. These include:
Breadth of Approvals: The existing global landscape of dispersant approvals is varied and needs to be understood in order to support international response readiness.
Availability/Diversity of data demonstrating effectiveness: It is important to have credible data relating to effectiveness on a wide diversity of oils (light to heavy, crudes to refined products) and how performance may be affected as oils weather. Performance data should be available that show how well products work at different temperatures and different dispersant to oil ratios. In general, it is important to ensure that selected products have the broadest applicability for the variety of circumstances that may arise.
Availability/Diversity of data on responder safety and potential toxicity to marine life: It is important to have as much credible data as possible with respect to any health concerns for response personnel and/or toxicity concerns regarding marine life. Availability of this information from reliable sources, e.g., peer reviewed journals and publications, is needed for regulatory approval and support of dispersant use decisions.
Stockpile Maintenance: A robust maintenance program is required to ensure the structural integrity and chemical quality/effectiveness of dispersant stockpiles.
Visual Inspection: Aligned with routine equipment maintenance programs, visual inspection focuses on storage conditions, identification labeling, container defects/damage, leaks and changes to colour and clarity over time.
Effectiveness Testing: A simple and repeatable sampling and chemical analysis protocol for dispersant effectiveness is necessary.
Two global Oil Spill Response Organizations (OSROs) with large scale dispersant stockpiles (i.e. Tier III Inventories) have collaboratively developed a large scale dispersant inventory management regime in consultation with the Oil and Gas Industry. This paper will describe the development and implementation of the regime and highlight some of the challenges including dispersant shelf-life, validity of testing data and regulatory approval.