API Publ 4699 pdf download.Strategies for Characterizing Subsurface Releases of Gasoline Containing MTBE The greatest concerns associated with gasoline releases have traditionally been non-aqueous phase liquids (NAPL) and dissolved-phase benzene, toluene, ethylbenzene, and xylenes (BTEX). The site characterization techniques commonly used by industry were originally developed to meet regulatory requirements for NAPL and BTEX. Over the past decade, however, there...