Respiratory assessment of refractory ceramic fibers in a heating technician population.

Refractory ceramic fibers (RCF) have been extensively used for insulation in condensing boilers. The aim of this study was to evaluate the respiratory exposure to these fibers among maintenance heating technicians. We first created a working group (Carsat Brittany and Finistère Occupational Health Services) and carried out a sampling strategy. Atmospheric measurements were done during work tasks, and filters were analyzed by phase contrast microscopy (PCM) and scanning electron microscopy (SEM) in French approved laboratories. Four companies were included for a total of 15 days of work. During those 15 work days, 12 SEM and 21 PCM samples were taken and analyzed. The phase contrast microscopy and SEM average results were 0.04 and 0.004 fibers/cm3, respectively. In conclusion, the study confirms heating technician RCF respiratory exposure during maintenance work for both condensation gas boilers and atmospheric boilers. Collective and individual prevention measures should be implemented along with appropriate medical follow-up.