The liabilities listed on the balance sheet of the U.S. government include a line item titled “Environmental and Disposal Liabilities.” These aren’t small potatoes – in 2015, they were estimated at $412 billion. Here’s a look at the reported amounts since 1999, when the line item first appeared:
What spills could possibly cost nearly half a trillion dollars to clean up?
Nuclear weapon and related weapons contamination, that’s what.
Since World War II, the U.S. government has manufactured tens of thousands of nuclear warheads and has conducted over 1000 nuclear tests. Nuclear contamination happened at every site where these activities were conducted.
The government accounts for these liabilities based on uncertain estimates of future clean-up costs. For a significant portion of the contamination, no technology is currently available for remediation; the government does not record a liability in these cases, but may in the future if the technology does arrive.
Nuclear contamination is not the only source of these liabilities, however. Large costs also loom for corrective actions necessary after the burial of chemical weapons.
Aircraft carriers last a long time, but they don’t last forever, and weapons disposal also costs money.
Significant uncertainties underlie these cost estimates. For the Department of Defense, these uncertainties are high in part for self-inflicted reasons. DoD regularly receives a disclaimer of opinion from the auditor of its financial statements, and this disclaimer cites material weaknesses in DoD's internal controls for accounting for environmental liabilities.