Soil with radiation contamination levels above 1.2 MBq/m2 was placed in 250-litre (66 U.S. gallon) drums and shipped to the Savannah River Plant in South Carolina for burial. A total of 2.2 hectares (5.4 acres) was decontaminated by this technique, producing 6,000 barrels. 17 hectares (42 acres) of land with lower levels of contamination was mixed to a depth of 30 centimetres (12 in) by harrowing and plowing. On rocky slopes with contamination above 120 kBq/m2, the soil was removed with hand tools and shipped to the United States in barrels.[19]
In 2004, a study revealed that there was still some significant contamination present in certain areas, and the Spanish government subsequently expropriated some plots of land which would otherwise have been slated for agriculture use or housing construction.[27] In early October 2006, the Spanish and United States governments agreed to decontaminate the remaining areas and share the workload and costs, which are hitherto unknown, as it first needs to be determined to what extent leaching of the plutonium has occurred in the 40 years since the incident.
On 11 October 2006, Reuters reported that higher than normal levels of radiation were detected in snails and other wildlife in the region, indicating there may still be dangerous amounts of radioactive material underground.[24] The discovery occurred during an investigation being carried out by Spain's energy research agency CIEMAT and the U.S. Department of Energy. The U.S. and Spain agreed to share the cost of the initial investigation.
In April 2008, CIEMAT announced they had found two trenches, totalling 2,000 cubic metres (71,000 cu ft), where the U.S. Army stored contaminated earth during the 1966 operations. The American government agreed in 2004 to pay for the decontamination of the grounds, and the cost of the removal and transportation of the contaminated earth has been estimated at $2 million. The trenches were found near the cemetery, where one of the nuclear devices was retrieved in 1966, and they were probably dug at the last moment by American troops before leaving Palomares. CIEMAT expects to find remains of plutonium and americium once an exhaustive analysis of the earth is carried out.[28] [29] In a conversation in December 2009, the Spanish Foreign Minister Miguel Ángel Moratinos told the US Secretary of State Hillary Clinton that he feared Spanish public opinion might turn against the US once the results of the study on nuclear contamination were to be revealed.[30]
In August 2010, a Spanish government source revealed that the U.S. has stopped the annual payments it has made to Spain, as the bilateral agreement in force since the accident, "expired", the previous year.[31]
As of 2012, Spain is asking the United States to finish cleaning up the area.[32]
