Oil Spill Response Gap

The Council believes that an oil spill response gap exists in Prince William Sound. A response gap occurs when oil can be transported in weather conditions not feasible for executing a successful oil spill response. For example, the closure limits to tanker traffic in Hinchinbrook Entrance are set at either 45 knot winds or 15 foot seas, but so far the industry hasn’t illustrated the capability to respond in weather conditions anywhere near those closure limits.

The response system in place today in Prince William Sound is the result of many years of development by industry, regulators, and the Council. Technical studies and analyses were done on response equipment and tactics based on varying weather conditions to develop the response capabilities in place to meet the response planning standard (able to contain and recover 300,000 barrels within 72 hours after a spill has occurred).

The Response Planning Group (RPG), a partnership of shipping companies, and the Alaska Department of Environmental Conservation (ADEC) recognize that the gap exists. ADEC and the RPG tried to quantify this in the early 1990s, with the result being a Realistic Maximum Response Operating Limitation (RMROL) set at 30-40 knot winds and ten foot seas with the idea that adequate prevention measures would mitigate the gap. Part of these prevention measures include tanker speed limits, ice detection strategies, and double tug escorts for each of the outbound tankers. However, the Council believes that even the RMROL agreed to in the contingency plans are still unrealistic and that the gap needs to be addressed. Since better weather station data now exists, the Council may revisit this issue and quantify, with real weather data, the frequency and severity of these response gaps.

In 2007, the Council hired Nuka Research & Planning LLC to assess the extent, seriousness, and possible mitigating measures of the response gap. Nuka completed two reports characterizing the response gap for central Prince William Sound and Hinchinbrook Entrance:

On the mechanical response gap:

The mechanical response gap report analyzes the ability to respond to a spill by mechanical means, such as using booms and skimmers. The gap is compounded by such factors as sea conditions, limited visibility, human factors, and other environmental and oceanographic factors that limit oil spill response. 

Response Gap Estimates for Two Operating Areas in Prince William Sound – 2007

Response Gap Methods

On the non-mechanical response gap:

The non-mechanical response gap report addresses response gaps that exist when responding with non-mechanical means, such as in-situ burning and dispersants.

Non-mechanical Response Gap Estimate: Literature Review and Recommended Limits – 2007 

Non-mechanical Response Gap Estimate for Two Operating Areas of Prince William Sound – 2008 

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