Questionable safety procedures, leaking ponds, inadequate monitoring and unreliable analytical methods are just some of the findings about coal seam gas activities at Santos sites in a report the Environment Protection Authority has tried to keep secret.

The report into CSG operations at Gunnedah and Pilliga was the result of an audit of the coal seam gas industry conducted by the EPA in May 2013 which was to have been released publicly to "build the profile of the EPA as the new lead regulator for the industry ... and to increase community confidence" in the regulation of the industry according to the EPA's own internal documents.

The EPA drew up a media plan to communicate the steps and results of the audit program - which included "state-wide media releases" - but then refused to release the report's details. It was only after a protracted freedom of information process by The Sun-Herald and the Greens that some information has come to be publicly released. An EPA spokeswoman said she was not aware of that communication plan.

The Santos site report revealed no groundwater monitoring was taking place at the Wilga power station site, the air pollution testing was not using prescribed methods, and "the reliability of any results obtained would not be assured".

The documents show that the EPA gave Santos several days' warning of the upcoming audit - a move the EPA knew would be of "interest to the media", according to internal EPA documents. The reason stated was the remote location of the sites.