Leak in Navy Fuel Tank Raises Concerns About Water Contamination

http://www.civilbeat.com/articles/2014/01/16/20941-leak-in-navy-fuel-tank-raises-concerns-about-water-contamination/
The U.S. Navy confirmed Thursday that one of its massive underground tanks near Pearl Harbor has a leak and may have spilled up to 20,000 gallons of aviation fuel, raising concerns about potential drinking water contamination.
The Red Hill Storage Tanks are an engineering marvel.  During World War II, dedicated workers carved space for twenty 20-foot storage tanks deep inside a hill on Oahu in only 3 years.

Here's the history behind them:

http://the.honoluluadvertiser.com/article/2007/Jun/13/ln/FP706130406.html
http://stott.com/2010/06/16/red-hill-underground-fuel-storage/
http://imagesdesavions.com/redhill/index.html (pictures)