A DNA segment involved in the regulation of the isopropylbenzene (cumene) catabolism operon (ipb) of plasmid pRE4 from Pseudomonas putida RE204 and the Vibrio fischeri luciferase genes, luxCDABE, were used to create an ipbRo/pA(prm1)-luxCDABE reporter fusion plasmid, pOS25. Escherichia coli HMS174(pOS25) produces light in the presence of inducers of the ipb operon. These inducers were shown to be hydrophobic compounds and to include monoalkylbenzenes, substituted benzenes and toluenes, some alkanes and cycloalkanes, chlorinated solvents, and naphthalenes. Complex hydrocarbon mixtures, such as gasoline, diesel fuel, jet fuels (JP-4 and JP-5), and creosote, were also inducers of ipb-lux. Bacteria carrying the ipb-lux reporter may be useful as bioindicators of hydrocarbon pollution in the environment and may be particularly valuable for examining the bioavailability of inducing pollutants.