The combination of element-specific investigation by low temperature gas chromatography coupled online with inductively coupled plasma optical emission spectroscopy (LT-GC/ICP-OES) and gas chromatography using mass spectrometry detection (GC-MS), as an additional analytical technique for molecular identification, was employed for the determination of volatile organosilicon species. Gaseous and liquid samples from waste deposit sites, waste composting tanks and sewage-disposal plants were investigated. It was frequently possible to identify the labile silanol compound trimethylsilanol as a dominant silicon species in waste disposal and waste composting gases. The results presented give rise to the assumption that trimethylsilanol is a volatile product of the degradation of organosilicon materials under special environmental conditions.