Laboratory Gas Chromatography/Mass Spectrometry (GC/MS) methods are normally employed to determine pentachlorophenol (PCP) and creosote contaminant levels in soil samples from hazardous waste sites. Laboratory GC/MS methods can be modified for field (on-site) use to provide timely results while maintaining high data quality. The U.S. Environmental Protection Agency's Environmental Response Team (U.S. EPA/ERT), through its Response Engineering and Analytical Contract (REAC), has developed field GC/MS methods to provide timely, reliable, and cost-effective PCP and creosote analyses needed by site managers to guide remediation and removal activities.