Abstract: A compact compressor is provided which can be used for production of very high-pressure end products using a multi-stage compression process. In one exemplary application, the compressor can be used for each stage of the multi-stage compression process used in production of compressed natural gas (CNG), in which low-pressure natural gas (NG) is compressed to less than 1 percent of its volume at standard atmospheric pressure (e.g., to 2,900-3,600 psi or 20-25 MPa). The compressor includes spark-avoidance, heat-mitigation and oil separation systems to safely and effectively produce CNG from NG.