Among all specific environmental pollution the chemical compounds released in the oil refine process seem to hold the biggest interest. At Medical University of Warsaw we have been studying the influence of the Płock petroleum refinery plant pollution to citizens' health status for over 30 years. The high amount of hydrocarbons--including benzene--were presented in emission. One of the study objectives was to analyze death causes in Płock and Kutno and in the Płock area--according to environmental criteria. The population of the non-petrochemic polluted city Kutno was chosen as the control group. The previous analysis in 1984-1993 showed increased lymphatic or erythrocyte line leukaemia mortality in Płock population vs Kutno population. Similar situation was observed between the area of increased environmental petrochemical pollution and non-polluted area. In this article the Potential Years of Life Lost ratio was used to estimate the life deficiency as the measure of health needs due to mentioned neoplasms. Data indicate that the health needs are bigger than the mortality analysis has shown.