For the most part, CEC's collected audio tapes preserve the broadcasts of a Radio Pacific (KPFT 90.1) show entitled "Talk of the Earth," a program format designed to inform the Houston audience with expert opinions on environmental issues. The Audio Tapes sub-series includes a few other tapes including recordings of some board meetings and a set of Department of Agriculture Public Service Announcements in Spanish. Including a few duplicates, the Audio Tapes sub-series contains 171 tapes organized in 10 boxes specifically designed for audio tapes.