Abstract: A process for remediating contaminated soil or groundwater using a strain of Pseudomonas paucimobilis designated NRRL B-18512 is disclosed. Further, the process is a two stage sequential process wherein in the first stage bacteria which degrade low molecular weight polycyclic aromatic hydrocarbons, heterocyclic organic compounds and phenolics are used in a pretreatment step. However, the remaining high molecular weight compounds are treated in a second step of the process with the Pseudomonas paucimobilis strain since the strain is not inhibited by low molecular weight compounds because these are removed in the first pretreatment step. Therefore, repeated inoculation of the strain is not necessary and the overall process disclosed eliminates the inhibitory effects of the low molecular weight compounds.