IP1597 - Australian dispersant acceptance processes - Rev 0 - October 2015

Joint NOPSEMA/AMSA explanatory note

This page provides an overview of chemical dispersant acceptance and decision-making processes for marine oil pollution response in Australian Commonwealth waters. This page describes separate processes that apply to the maritime and offshore petroleum industry sectors.

Note: the following is provided for general information only – please refer to amsa.gov.au and nopsema.gov.au for further guidance on the requirements of the maritime and offshore petroleum industry sectors respectively.


Chemical dispersants are designed to enhance dispersion of oil slicks by encouraging the oil to break into microscopic droplets that can be bio-degraded by marine micro-organisms. Dispersants may be sprayed at the sea surface to break up oil slicks or applied to subsea spill sources to prevent oil reaching the surface. This can prevent slicks from reaching sensitive coastal environments and reduce impacts on marine fauna and birds. However, the positive effects of reducing impacts at the surface need to be weighed against potential dispersed-oil impacts on marine organisms beneath the surface.

There is typically a limited ‘window of opportunity’ to apply dispersants before oil weathers and/or reaches sensitive resources. Timely dispersant acceptance and decision-making processes are essential to ensure that this response strategy is implemented in a manner that achieves the desired result.

Dispersant acceptance and decision-making in Commonwealth waters

Dispersant acceptance and decision-making processes require determining which products are acceptable for use, when they should be used and appropriate application strategies. Two separate dispersant acceptance and decision-making regimes apply to the maritime and offshore petroleum sectors in Commonwealth waters (Figure 1).


Image - IP1597

Figure 1. Overview of dispersant acceptance regimes for Commonwealth waters.


The principal differences between the two regimes reflect the different pollution risks of each sector. Maritime pollution incidents are typically spills at the sea surface of a range of possible oil types and may occur in any of the different environmental conditions found throughout Commonwealth waters. In contrast, offshore petroleum pollution risks are related to location-specific activities with largely known or predictable oil types and may involve surface or subsea spill sources.

The maritime regime is based around testing and registering dispersant products as acceptable for ‘general purpose’ use prior to an incident. The decision on whether to use dispersants is then based on the circumstances of each maritime incident. The offshore petroleum regime, as reflected in specific legislation, requires that all pollution response arrangements for a petroleum activity must be accepted by the regulator prior to an activity commencing. These response arrangements address specific requirements for timely implementation of dispersants, including product selection, deployment strategies and monitoring, in advance of any activity commencing.

Maritime sector – AMSA: National Plan OSCA Policies and Register

The Australian Maritime Safety Authority (AMSA) manages the National Plan for Maritime Environmental Emergencies[i] (the National Plan). Under the National Plan dispersants are classified as oil spill control agents (OSCAs) and only those products listed on the National Plan OSCA Register can be added to National Plan stockpiles or considered for use in maritime pollution incidents.

The National Plan Policy for registering OSCAs (the OSCA Policy[ii]) requires a manufacturer or distributor to demonstrate that their dispersant meets predetermined requirements for efficacy, toxicity and biodegradation. A separate policy (OSCA Guideline Twoii) provides guidance on best practice decision-making processes for obtaining approval to use dispersants listed on the OSCA Register during maritime spill responses. These policies only address the application of dispersants at the sea surface.

Appropriate use of dispersants listed on the OSCA Register in Commonwealth waters is protected under an exemption[iii] under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

Offshore petroleum industry – NOPSEMA: Environment Regulations

The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) administer the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 (Environment Regulations). The Environment Regulations require that an offshore petroleum activity must have an environment plan (EP), which includes an oil pollution emergency plan (OPEP), accepted by NOPSEMA before the activity commences[iv]. An EP must detail control measures, encompassing all proposed pollution response strategies that will be used to reduce oil pollution risks to as low as reasonably practicable (ALARP) and an acceptable level[v].

The EP submission process provides the mechanism for an offshore petroleum titleholder to gain ‘acceptance’ for the use of location, activity or OPEP specific oil spill dispersant products and deployment strategies (e.g. surface and/or subsea application) prior to any incidents. This provides a titleholder with the ability to identify the most appropriate dispersant response options to match its environmental risks and response requirements.

Any dispersant use in response to a pollution incident from an offshore petroleum activity must be carried out in accordance with an accepted EP and no additional ‘approvals’ are required to implement these response arrangements.

Impacts of petroleum activities on matters protected under Part 3 of the EPBC Act are assessed by NOPSEMA under the Environment Regulations[vi]. This has the effect that any dispersant products or strategies detailed in an accepted EP have been assessed against any EPBC Act requirements through the NOPSEMA assessment process.

Petroleum titleholders may decide to refer to a dispersant product listed on the OSCA Register to support the demonstration that its use is acceptable and ALARP for pollution incidents arising from its activity. However, listing of a particular dispersant on the OSCA Register alone does not mean that NOPSEMA will automatically accept its use in a spill at an offshore petroleum activity. It may be more appropriate, for example, to test dispersant efficacy with oil(s) relevant to that activity and/or toxicity with species relevant to its geographic location not covered by the OSCA Policy. There is also no regulatory requirement for a titleholder to restrict its evaluation of dispersants to only those products listed on the OSCA Register. Further, there is no requirement for an accepted EP-specific dispersant to be subsequently listed on the OSCA Register.