Due to its nature, the activity of mills promotes the suspension of fine flour, grain or bran in the air. This can lead to the formation of explosive atmospheres (ATEX) into process equipment (silos, mills, handling equipment or dust collectors), but also in working areas. The objective of this study is to assess the management of this risk by companies in the milling sector. This investigation is mainly carried out in the Île-de-France region, within the framework of a French National Social Insurance prevention program. Two approaches were combined: an accident database managed by the Government was thoroughly examined and additional visits were performed in several companies representative of this sector. More than 600 fires and explosions, that occurred between 1975 and 2021, were investigated through statistical methods.
This study shows that, although regulations have been applicable since 2003, the management of the fire and explosion risks is very disparate, depending on the culture of the company and its organization. In some facilities, the risk associated to ATEX formation and ignition is significant and is greatly underestimated. In such cases, the analysis of accident feedback shows that in more than one third of the cases, similar negligence has led to multiple accidents. Moreover, factors such as the grain nature, the lack of quality control of raw materials or maintenance deficiencies play a significant role on accident likelihood and on the primary failure mode. This work allows the definition of a more targeted actions intending to enhance the milling companies awareness and convince them act on this particular risk.