Optimising dispersant selection for offshore pollution risks

Article published in the Regulator | Issue 3: 2015

NOPSEMA and the Australian Maritime Safety Authority (AMSA) have jointly produced an explanatory note describing the separate dispersant acceptance and decision-making regimes that apply to the maritime and offshore petroleum sectors in Commonwealth waters.

Chemical dispersants are one of the principal control measures available for oil spill response in Commonwealth waters. However, there are considerable community misconceptions about these products and the potential net environmental benefit of dispersant response strategies. Dispersant decision-making requires determining which products are acceptable for use, when they should be used and the appropriate application strategies.

The maritime regime focuses on testing dispersant products against defined effectiveness, toxicity and biodegradability criteria for ‘general purpose’ use in surface spills. Dispersants that meet these criteria can be accepted for listing on The National Plan for Maritime Environmental Emergencies (The National Plan) oil spill control agent (OSCA) register. The decision on whether to use a ‘listed’ dispersant is then based on the circumstances of each maritime incident. In contrast, the offshore petroleum regime requires that all pollution response arrangements for a petroleum activity, including dispersants, must be accepted by NOPSEMA prior to an activity commencing.

The environment plan submission process is the mechanism for offshore petroleum titleholders to gain acceptance for the use of location, activity or oil pollution emergency plan specific oil spill dispersant products and deployment strategies (e.g. surface and/ or subsurface application) prior to a pollution incident. This provides a titleholder with the ability to identify the most appropriate dispersant options to match its environmental risks and response requirements, including new and improved formulations that may not always be listed on the OSCA register. Titleholders are required to demonstrate that the environmental impacts and risks of any proposed dispersant use will be reduced to as low as reasonably practicable (ALARP) and of an acceptable level in an offshore pollution incident.