"INTRODUCTION Gasoline consists of a mixture of aliphatic and aromatic hydrocarbons with most components having a carbon chain of four to eight. Multi-component mixtures can present certain problems for general organic vapor air monitoring procedures such as selective adsorption of certain components@ stripping of other components@ adsorption/desorption fractionation@ solvent Interference with components@ and others. The American Petroleum Institute (API) sponsored this effort to evaluate and standardize sampling and analytical methods for monitoring gasoline vapors in the workplace. Sampling and analytical methods for monitoring exposure to gasoline vapors in the workplace were evaluated for precision and accuracy and equivalency under varied relative humidity conditions and vapor concentrations. Sampling methods studied included charcoal tube and passive dosimeter collection. The analytical method used for all sampling media was based on PCAM 1271 which utilizes carbon disulfide desorption followed by gas chromatographic (GC) analysis. This method was modified for gasoline vapor with adaptations including type of desorption solvent and GC conditions utilized. Details concerning the experimental protocol@ analytical program@ test system@ results@ and conclusions are presented@ herein. (1) ""NIOSH Manual of Analytical Methods""@ Vol. 1@ PCAM 127@ 1977."