236 Occupational exposure to microorganisms and endotoxin during treatment of offshore drilling waste

Introduction The aim of this study was to describe the occupational exposure to microorganisms and endotoxin, for workers employed in the recycling of offshore drilling waste. A pilot study on two treatment plants, showed presence of human bacterial- and fungal pathogens in the drilling waste and showed a need for this larger study. Methodology The study included 7 different plants across Norway, thus encompassing most of the industry. 435 personal full-shift analyses, 26 bulk samples and 123 stationary short-time samples of microorganisms were collected. Viable bacterial and fungal species were identified with MALDI-TOF, and bacterial and fungal DNA with ddPCR. The biofilm formation potential was also measured using an Epoch microplate spectrophotometer. Results Even though mean exposure was low, some workers were exposed to high levels of endotoxin (207 EU/m3), bacteria (3.8x104 CFU/m3 and 9.8x104 DNA copies/m3) or fungi (1.4x107 CFU/m3 and 3600 DNA copies/m3). The drilling waste contained a high number of bacteria (102 to 1010 CFU of bacteria/mL) and pathogens in risk class 2 were found in all plants. The biofilm formation potential varied between the different plants. Conclusions Despite moderate exposure levels, certain work tasks, job titles, areas, and techniques, were associated with elevated levels of microorganisms and endotoxin. Human pathogens were present in the drilling waste, the workers can be exposed via the air and potentially via splashes.