Last year at this meeting we reported the presence of our unique keto fatty acids present in postmortem lung lavage of cotton mill workers (1). These compounds showed high levels of cytotoxicity toward cultured mammalian KB cells and were general activators of inflammatory cells (2). The observation that the presence of these acids correlated with cotton mill exposure has led us to develop a rapid screening method using Fast Atom Bombardment Mass Spectrometry for the detection of these compounds in human bronchoscopic lavage.