Assessment of occupational exposure to gasoline vapour at petrol stations

Abstract

Petrol station attendants’ exposure to gasoline vapours while refuelling vehicles has raised health concerns, especially in tropical countries like Saudi Arabia. This is due to the increase of gasoline vaporisation by the high temperatures and related weather conditions. This represents an increase risk of inhaling more vapours than its counterpart temperate countries. Furthermore, exposure during extended working hours (12 hrs shifts), with no vapour recovery system and the handling of gasoline containing a high percentage of volumes of toxic substances (e.g. BTEXs) have not been adequately addressed previously in Saudi Arabia. Therefore, this study was designed and carried out to investigate the validity of this concern by assessing and quantifying full shift exposures to gasoline vapours during the petrol filling process. Different exposure assessment methodologies were employed and evaluated for their suitability. The study assessed the exposures of 41 attendants via passive, active, and direct reading methods at twelve petrol stations with both high and low sales in the Eastern Province of Saudi Arabia. The study was conducted during the winter and summer months to test the seasonal variation of the pattern of exposure. The effects of the quantity of gasoline sold, the locations of the stations, weather variations (e.g. wind speed, temperature, and humidity) were tested. A purpose built mini-weather stations and modified thermometres were utilized to accurately monitor the prevailing weather conditions. Forward-looking infrared (FLIR) thermal image cameras were utilised to visualise the size and movement behaviour of the vapour plumes during petrol refuelling. Furthermore, analytical lab trials were carried out to characterise the gasoline vapour component under different temperatures. These were used to propose a new OEL. The geometric means of the personal passive results for BTEX and MTBE (0.18 ppm, 0.24 ppm, 0.09 ppm, 0.18 ppm, 1.57 ppm, respectively) were found to be relatively higher than those reported previously for Europe and North America. These results are discussed in the context of the impact that such exposure will have on people involved in this industry in petrol stations in Saudi Arabia.