In our paper ‘Petroleum refinery effluent contribution to chemical mixture toxic pressure in the environment’ (submitted), we developed a generic methodology to assess the petroleum refinery effluent (PRE) contribution to mixture toxic pressure in the environment, using the multi-substance potentially affected fraction of species (msPAF) as an indicator. Based on measured chemical concentrations, compiled species sensitivity distributions (SSD) and dilution factors, msPAF levels were estimated for undiluted effluents at discharge points and diluted effluents downstream in receiving waters. Regardless of differences in endpoints and locations, hydrocarbons (mainly total petroleum hydrocarbons) and inorganics (mainly ammonia) explained at least 85% of the mixture toxic pressure. The msPAF levels of PREs were on average 2.5-4.5 orders of magnitude lower than background levels, suggesting that PREs were minor contributors to the toxic pressure in the environment.This dataset contains data on estimated msPAF levels for different refinery effluents (present study) and estimated background msPAF levels in the corresponding basin calculated by Posthuma et al. (2019).