FORT DRUM — Post officials are estimating that 350,000 gallons of jet fuel, discovered to have leaked into the ground at Wheeler-Sack Army Airfield in April 2006, could take up to 10 years and $10 million to clean up.
"It's going to be in the millions," said James W. Corriveau, Fort Drum's public works director. "No one knows for certain."
To date, the cost of recovering 32,000 gallons has been $2 million. Fort Drum officials, who have been drawing the fuel through five wells, expect to add 10 more wells this summer to the tune of $900,000.
Once the 10 additional wells are online, Mr. Corriveau said, recovery of the underground fuel plume will increase from 400 gallons per week to 1,500 gallons per week.
The cost of the cleanup will be paid by the Defense Energy Support Center in Fort Belvoir, Va., which oversees fuel use for the military.
The recovered fuel is expected to be shipped to a recycling plant where it will be processed and returned to the military for use in heating plants or as vehicle fuel.
While no one is completely sure when the leak started — Mr. Corriveau said it might have been as early as 2001 or 2002 — the base Department of Public Works first identified a leak in April 2006. The spilt fuel was traced to a faulty valve on a sump beneath a refueling oasis on the airfield's tarmac.
Fort Drum maintains a supply of about 290,000 gallons of jet fuel; consumption at Wheeler-Sack ranges anywhere from 100,000 to 700,000 gallons a month depending on the amount of activity at the fort.
The Watertown Daily Times first reported in December 2006 that Fort Drum had shut down seven active wells as a precaution after pumping 3,500 gallons of fuel out of a manhole.
By February 2007, Fort Drum had agreed to pay EA Engineering, Science and Technology of Syracuse $373,000 to dig approximately 50 wells on the airfield to try to gauge how far the leak spread.
A month later, Fort Drum estimated the jet fuel leak was between 225,000 and 275,000 gallons.
An erroneous keystroke in a computer model led Army officials to revise that number down to 160,000 gallons, plus or minus 40,000 gallons, in November.
The number went back up to 350,000 gallons this week, after the Department of Public Works asked EA Engineering to revise the computer model. An investigation by WWNY-TV news also identified the discrepancy and noted that three years of fuel inventories had tracked constant fuel losses at the airfield.
"The numbers keep moving around because we're learning about the spill," Mr. Corriveau said. "It's 44 feet below ground; you can't reach down there and touch it."
The sheer volume of fuel used at the airfield each month meant even 350,000 gallons of missing fuel went unnoticed.
Although estimates on the extent of the leak have changed in the past two years, the egg-shaped plume itself has remained relatively stable. The plume sits on the surface of the groundwater 44 feet under the airfield and is believed to be 450 feet by 550 feet in size.
"The size of the spill isn't growing," said Steven W. Litwhiler, state Department of Environmental Conservation spokesman. "We hope it's going to keep on going down as it's getting cleaned up."
Mr. Litwhiler and Mr. Corriveau agree the fuel does not pose a danger to surrounding municipal water supplies, although it should be cleaned up as quickly as possible. Besides recovering the plume of 350,000 gallons of fuel, Fort Drum eventually will have to recover and clean the 44 feet of soil above the plume and the contaminated water beneath it.
In the meantime, Fort Drum officials are confident enough in the stability of the plume that they expect to bring eight wells near the airfield back online this summer.
Fort Drum also plans to recommission a system of fueling helicopters while they are running that also has been shut down for two years.
About $3 million is being spent to restore the fuel system, expected to be in operation by late summer 2009, Mr. Corriveau said. This time it will include watertight manholes, rebuilt components and an alarm system to detect any fuel leaks.
