Summary: Pursuant to a congressional request, GAO determined whether the Department of Energy (DOE) or its Hanford, Washington, site contractor fully disclosed the volume of waste that leaked from the site's underground single-shell storage tanks.
GAO found that: (1) DOE estimated that 750,000 gallons of liquid waste leaked from 66 shell tanks, but did not include the volume of cooling water that had been added to the tanks, some of which could have leaked; (2) DOE historically did not include cooling water that could leak from the tanks in its tank leak studies; (3) DOE noted that it added cooling water to a single tank and that some did leak, but did not provide any volume figures; (4) the contractor's estimate indicated that only 5,000 gallons of waste leaked from that tank, but records indicated that more than 500,000 gallons of contaminated cooling water leaked from the tank; (5) as of February 1991, the contractor estimated that between 50,000 gallons and 800,000 gallons of the cooling water added to the tank between February 1971 and December 1978 could have leaked; and (6) in October 1990, DOE directed the contractor to examine past records to determine the amount of liquid waste that could have leaked from the 66 tanks classified as assumed leakers, including the aforementioned tank.
