Fuel is proving to be a very volatile commodity for the Pentagon as operations heat up in Afghanistan.

The Pentagon spent about $4.8 billion on fuel and liquid propellants in 2009, making them the third-highest expense for the U.S. military last year, according to an Aerospace DAILY analysis of federal contracting data provided by the National Institute for Computer-Assisted Reporting.

The 2009 fuel bill was about 55% more than the Pentagon’s 2008 fuel purchases, when those costs ranked as the fourth-highest Pentagon expense, the analysis shows.

About a quarter of all the 2009 fuel contracts and contract modifications for 2009 originated in Afghanistan, although those transactions represent only about 2.6% of the total fuel expense amounts.

Altogether, the Pentagon awarded 114 contracts or modifications originating in Afghanistan for fuel, at a total price of about $126.9 million.

The only country with more originating contracts is the United States, with 296. The next highest countries after Afghanistan are Germany and Japan, with six transactions each.

What the large number of relatively low-priced fuel transactions in Afghanistan shows, analysts say, is the need to buy fuel locally in Afghan regions because U.S. military supply lines are stretched thin and proving unreliable.

The analysis also highlights another trend in Pentagon fuel contracts in Afghanistan -- a reliance on unidentified contractors for the work. Pentagon contracts -- even classified ones -- have long identified the names of contractors in publicly releasing the transactions. In 2008, though, the Defense Department started to withhold those names, simply referring to them as "not available."

The Pentagon will not comment on the practice, but analysts say part of the reason for withholding the names is because the Defense Department has started to hire a large number of small companies that have sprung up in Iraq and Afghanistan to provide services like fuel and security.

The "not available" companies rank 10th among contractors with fuel contracts for 2009, tallying about $35 million in transactions. All of those deals originated in Afghanistan.

Recently, U.S. authorities reportedly started to investigate whether two companies that were part of a Pentagon Afghanistan fuel contract -- Afghan-owned Guzar Mir Bacha Kot Transportation, known as GMT by U.S. officials, and subcontractor Suleiman & Sons -- helped soldiers steal $1.6 million in fuel from the Logar province region military installation.

Neither company shows up as a named contractor for fuel contracts in 2009, according to the analysis.

Photo credit: U.S. Army