||Eight polybrominated diphenyl ether (PBDE) congeners of primary interest to the US EPA (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) were separated using reverse-phase liquid chromatography on an octadecylsilane column. Negative-ion atmospheric pressure photoionization (NI-APPI) with a toluene dopant produced [M-Br+O] - precursor ions and were quantified by tandem mass spectrometry through a unique, multiple reaction monitoring (MRM) transition. The LC/NI-APPI/MS/MS method was validated for the analysis of the eight PBDE congeners in NIST SRM 2585 (Organics in House Dust). Pressurized liquid extraction (PLE) with subsequent LC/NI-APPI/MS/MS analysis afforded quantitative recovery for all eight PBDE congeners with recoveries ranging from 92.7 to 113%. LC/NI-APPI/MS/MS method is not prone to the thermal degradation issues that plague splitless GC based analyses of highly brominated PBDEs such as BDE-209. The LC/NI-APPI/MS/MS method was used to measure the levels of the eight PBDE congeners were determined in the dust sampled from 60 automobiles that were available for resale at U.S. dealerships. The dominant congener in automobile dust was BDE-209 comprising 95% of the total PBDE levels with a median level of 48.1 μg g -1 . Statistical analysis of the vehicle attributes indicates that the BDE-209 levels are different ( p < 0.05) with respect to groupings by vehicle model year, vehicle manufacturer, and the country of manufacture. Vehicle dust samples contained the characteristic percentages of the PBDE congeners that comprise the PentaBDE formulation. Exposure calculations estimate the adult and child median total PBDE daily intakes from automobile dust at 54.9 and 96.1 ng day -1 , respectively. Median exposure to PBDEs from vehicle dust in adults and children is equivalent to the exposure estimates calculated from indoor dust levels and represents a significant, unaccounted body burden in the U.S. population. While DecaBDE use is banned in Maine and Washington and is targeted for restriction in the near future by six U.S. states, vehicles and airplanes are exempt from the ban. It is anticipated that the human exposure potential to PBDEs from automobile dust ingestion will continue for an indefinite future period in the U.S. population.