This article is a commentary on the following study: Pitarque M, Creus A, Marcos R, Hughes JA, Anderson D. Examination of various biomarkers measuring genotoxic endpoints in Barcelona airport personnel. Mutat Res. 1999 Apr 6;440(2):195-204. The objective of this study is to examine the genotoxic effect of exposure to monocyclic aromatic hydrocarbons among employees at Barcelona Airport using various blood biomarkers of effect, in comparison with controls with no known exposure to genotoxic substances. This unconvincing study does not provide clear evidence regarding the genotoxic effects of benzene and its alkylated derivatives in humans during chronic low-dose exposure, particularly due to the limitations of the protocol regarding the assessment of environmental exposure. (Excerpt from the article)