Today SkyTruth released our Site 23051 Cumulative Spill Report showing our estimation of the total cumulative amount of crude oil spilled into the Gulf of Mexico at the site of Taylor Energy's ongoing oil spill that began in 2004. In this report, we conclude:
- Crude oil has been leaking continuously from this site for more than 7 years
- Estimated cumulative volume of crude oil spilled is between 251,677 and 1,174,492 gallons
|Radar satellite image of 21-mile-long slick apparently emanating from Site 23051 on July 16, 2011. Envisat ASAR image courtesy European Space Agency.|
There are two key assumptions we used to compute the average daily flow rate:
- Average oil thickness in observable slicks
- Average rate of degradation of an oil slick, expressed in terms of a half-life
Combining all our data on slick extent with the high and low values for each of the key assumptions, we get 4 values for estimated cumulative oil spilled (see the calculations):
|Half Life (days)||Thickness (microns)||Estimate(gallons)|
SkyTruth, the Gulf Monitoring Consortium and others have been actively monitoring this site for 21 months since May of 2010 (during what turned out to be the early days of the massive BP/Deepwater Horizon spill), when we noticed on our satellite images another much smaller slick about 11 miles off the tip of the Mississippi River Delta.
Since then, we have analyzed historic satellite imagery back to the beginning of the spill, and we have waded through the spotty but extensive public record of official pollution reports filed with the National Response Center. Site 23051 also featured prominently in the recent Gulf Monitoring Consortium report, and earlier this month Waterkeeper Alliance announced a lawsuit against Taylor Energy over the ongoing spill.
Other Sources of Estimates
As far as we know, our report is the first comprehensive attempt to estimate the total amount of oil spilled at this site. However, the Coast Guard was recently quoted in an AP news article as saying "a total of 12,720 gallons of oil have been reported from daily observations since the spill started in 2004".
We called the Coast Guard last week and asked them where that number came from, and they told us "Approximately 12,720 gallons have been reported from daily observations (over flights) as of 2/2/12." Today we followed up and the Coast Guard told us that this number is the total of all the reports filed with them by Taylor Energy who is conducting the regular overflights, but they could not say how many reports this represents.
We asked them to investigate and get us a breakdown of exactly what they added up to get this number, especially what days are actually covered in that total, but as of this writing we do not have an answer. However, if their reporting record is as spotty as the public NRC record, then this number likely only captures a fraction of the true amount.
More on this under-reporting problem coming soon, so stay tuned.
Parting Thought: Worst-Case Scenario?
The environmental and economic damage from this chronic spill may be relatively minor, although if you ask a biologist and tell her it's a 1.2 million gallon spill, you might get a different answer than if you tell her it's only a 12,000 gallon spill. But imagine that the same event that wiped out Taylor's platform just 11 miles off the coast, had instead happened at a deepwater platform 100 miles offshore.
More on that later.