The Ministry of Environmental Protection refused to release data from a national soil contamination investigation launched in 2006, saying it involved national secrets, the Legal Daily reported on Monday.

The response was given in a letter on Sunday to Dong Zhengwei, a Beijing lawyer, who asked the ministry via an e-mail on Jan 31 to release information about the 2006 soil pollution investigation.

After the investigation, the ministry said it will release the results after approval by the State Council, but Dong believes that the ministry didn't release the data because the pollution is severe.