Estimates were made in the spring, before the financial crisis deepened.
But the energy agency's estimates were made when oil cost just $25 a barrel.
He added, however, that the lower estimates were made public last month as part of a budget document.
Detailed cost estimates were made, and there was extensive outreach to local officials, victims' families, and security personnel.
Since those estimates were made a few years ago, some of those acres have surely been developed.
No comparable estimates were made in previous years, the official said, but the widespread opinion among government officials was that the number was uch smaller 10 years ago.
The estimates were made largely by computer analysis of the genome sequence, and some scientists have long maintained that many genes were missed.
Some epidemiologists have criticized for years the way estimates were made, and new surveys of thousands of households in several countries have borne them out.
Gen. Don T. Riley, the head of civil works for the corps, said the costs rose because the earlier estimates were made in haste and under emergency conditions.
The hard estimates were made up until the year 2020.
While no population estimates were made, earthworms were commonly observed during sampling on the Argonne.
