132a - Assessing exposure to carbon nano fibres and carbon nano tubes in a production facility

Abstract Nanomaterial use and manufacture is a rapidly expanding field. Small and emerging companies make up a large portion of producers and the risks of exposure to nanomaterials (NMs) may not be known by producers. Additionally, occupational hygienists could lack knowledge or equipment necessary to measure the NMs. As these NMs do not contribute to the mass, a mass-based approach may not be suitable and there exist few occupational exposure limits available specific for NMs. However, the national institute of occupation health (NIOSH, US) recommends measuring respirable elemental carbon (EC) to evaluate exposure for carbon nano fibres (CNF) and carbon nano tubes (CNT). NIOSH then recommends that the respirable EC should be below 1 µg/m3 for 8 hours of exposure. The presence of CNF or CNT should also be confirmed by electron microscopy and parallel samples should therefore be collected. In this work, personal samples and stationary samples for EC and electron microscopy were collected at a small production facility in Norway where CNT and CNF were produced. The workers performed different tasks, such as crushing product, sieving, sandblasting as well as cleaning and maintenance of the furnace and handling of finished products. Additionally stationary equipment was a scanning mobility particle sizer (SMPS) and a 13 stage NanoMOUDI impactor. The results show that even though the exposure in most cases were below the recommended value of 1 µg/m3 for respirable EC, there is an exposure to CNT/CNF and measures to limit the risk of exposure should continue.