GASEOUS TRACE CONTAMINANT REMOVAL: The Gaseous Trace Contaminant Removal (GTCR) system removes harmful and/or unpleasant gases from the atmosphere that exist in trace amounts. The primary purpose is to remove Volatile Organic Compounds (VOCs) and to keep them below the Space craft Maximum Allowable Concentrations (SMACs). The GTCR does this by using a combination of granular filter beds and a catalytic oxidation bed.