[Continuing investigation of effect of toner and its by-product on human health and occupational health management of toner].

Objective: As there are reports that ultrafine particles are generated by thermal printer toner, and that mucosal irritation symptoms were observed in users. When printers were operated, we have been examining the effects of not only toner but its by-products on human health.

Methods: We conducted a review of epidemiological and animal data on toner and its by-products such as ultrafine particles and volatile organic compounds (VOC). This was the second survey and it confirmed the results of the first survey.

Results: We reviewed the data, and summarized the results as follows. 1) Four cross-sectional studies reported no definite harmful effects of toner. 2) Ultrafine particles were generated in greater numbers at higher fuser heating and higher toner coverages. Ultrafine particles were also observed at lower rates in idle mode. 3) High-sensitive c-reactive protein in serum and heart rate variability (HRV) were useful biomarkers of not only exposure to ultrafine particles but disorder of cardiovascular disease, 8-hydroxydeoxyguanosine in urine is a biomarker of acute lung injury by welder fume, and VEGF and CA15-3 are highly sensitive and specific biomarkers of pulmonary fibrosis. 4) Physico-chemical properties of ultrafine particles were examined, and specific parameters related to pulmonary responses were not observed.

Conclusions: Taken together, we found that there are some biomarkers which are related to not only exposure and but disorders induced by ultrafine particles, and that the generation of ultrafine particles with the operation of printers was associated with other factors than the fixing process. Until now there has been insufficient data for estimation of the hazards of toner and its by-products. However, continuing examinations are useful for complementing and correcting the information and data on toners and for revising the measures of occupational health. We will continue these examinations of toner and its by-products in the future.