As yet, no human studies describing the health effects from exposure during recycling of slurry containing SiC and/or PEG have been reported. However, there are several studies that may be relevant which assess the health effects of other particles. It has been demonstrated that small particles penetrate further into the lungs than larger particles and thereby have stronger irritating properties [2]. Results from 2 experimental studies where the effect variables were lung function, organ weights and characteristics of broncho-alveolar lavage (BAL) [3, 4] indicate that SiC dust and PEG itself are probably relatively inert. However, in a third study it was demonstrated that SiC particles have the potential to stimulate test cells (murine macrophage cell line and human osteoblast-like cell line) to produce inflammatory signal substances (tumour necrosis factor (TNF)-alfa), indicating possible inflammatory responses in the lungs [5]. Furthermore, it is thought that the total amount of inhaled dust is important ("overload") even if the substance itself is relatively inert [6]. Repeated high exposures (peaks) may act as a reinforcing factor.