We propose to apply an innovative non-targeted biomonitoring method using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) to evaluate everyday exposure to over 700 chemicals classified as Environmental Organic Acids (EOAs) and the extent to which exposures vary amount different racial/ethnic and socio-economic groups of pregnant women. Our new LC-QTOF/MS non-targeted screening methodology has the capacity to directly (without enzymatic hydrolysis) and simultaneously screen for approximately 10-times more EOAs than what is currently being biomonitored in the National Health and Nutrition Examination Survey. We focus on EOAs, which are industrial compounds with at least one ionizable proton, because: 1) their chemical structure facilitates a higher rate of analytical detection; 2) many of their chemical structures are similar to hormones, increasing the potential for endocrine disruption, which can negatively affect fetal development; and 3) many are produced in high quantities and used in a wide range of consumer products, but have not been extensively biomonitored in pregnant women. We will use liquid chromatography tandem mass spectrometry (LC-MS/MS) to confirm the presence and levels of select EOAs identified through our non-targeted screening. Finally, we will assess differences in EOA exposures by race/ethnicity and socio-economic status. We hypothesize that pregnant women are exposed to more EOAs than previously documented, and that EOA exposure varies by race/ethnicity and SES, resulting in disproportionate EOA body-burdens among certain subpopulations.