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Upon recovery, the sample container is sealed to mi iimize the potential of volatilization and cross-contamination prior to chemical analysis. Soil sampling tubes are typically closed at each end with i Teflon®sheeting and plastic caps. The sample is then placed in a Ziploc®type bag and sealed. The sample is labeled and refrigerated at approximately 40 Celsius for delivery, under strict chain-of-custody, to the I analytical laboratory. Sample Identification and Chain-of-Custody Procedures Sample identification and chain-of-custody procedures do ument sample possession from the time of collection,to ultimate disposal. Each sample container submitted for analysis has a label affixed to identify the job number, sampler, date and time of sample collection and, a sample number unique to that sample. This information, in addition to a description of the sunple, field measurements made, sampling methodology, names of on-site personnel and any other pertinent field observations is recorded on the borehole log or in the field records. A California-certified lab matory analyzes the samples. A chain-of-custody form is used to record possession of the sample from time of collection to its arrival at the Iaboratory. When the samples are shipped, the person in custody of them relinquishes the samples by signing the chain-of-custody form and noting the time. The laboratory sample-control officer verifies the integrity of the sample and confirms the samples are collected in the proper containers, preserved correctly and contain adequate volumes for analysis. If these conditions are met, each sample is assigned a unique log number for identification throughout analysis and reporting. The log number is recorded on the chain-of-custody form and in the legally required logbook maintained by the laboratory in the laboratory. The sample description,date received,client name and other relevant information is also recorded.