Health hazard assessment of colour print toner dust

Status:

completed 01/2001

Aims:

The market share of colour photocopiers and colour laser printers is on the rise. It can be assumed that colour laser printers, in particular, will increasingly be purchased in the near future for use in smaller offices. As the available toxicological and occupational medical data relating to colour toners have up to now been inadequate, the institution for statutory accident insurance and prevention in the administrative sector launched a project to examine whether the use of colour print toners for the production of photocopies or laser printouts involves avoidable health hazards which are inherent to the process. The results were to be used for the formulation of requirements for this type of equipment.

Activities/Methods:

The following parameters were measured for selected devices of modern design (three colour laser printers, three colour photocopiers) and the corresponding toners: propensity of the toner powder for dust production; effects of toxicological relevance upon macrophages isolated from guinea pig lungs; physical and chemical characteristics of particulate and gaseous emissions from colour photocopiers/colour laser printers, together with bacterial tests of their potential toxicological effects. The studies of the emission characteristics were performed with the devices in continuous operation (two hours or 800 copies/printouts) in an enclosed test chamber with a volume of approximately 9 m³. The project was supported by a working group in which equipment manufacturers and members of the BG expert committee in the administrative sector were also represented.

Results:

Like black toners, colour toner powders exhibit a strong propensity for dust production, in accordance with their function. In high concentrations, the toners had in some cases a harmful effect upon guinea pig alveolar macrophages, or induced secretion of the mediator TNF-alpha. These findings are interpreted as an indication of irritation and infection in the lung following the inspiration of very large quantities of toner dust. The toner compounds tested contained no detectable quantities of cadmium, cobalt, nickel or lead. Following reductive processing, trace quantities of carcinogenic amines were detected in some test samples. A photocopier which had not been maintained in accordance with the producers recommendations emitted comparatively high quantities of ozone. The ozone formation was however reduced considerably following professional adjustment. Two laser printers failed to increase the ozone concentration in the test chamber, even during continuous testing. Only one photocopier exhibited substantial emissions of benzene and some alkylaromatics during use. The concentrations measured remained well below the applicable atmospheric limit values for workplaces, however. In a sensitive toxicity test involving luminescent bacteria, the gases collected whilst the device was in operation exhibited only minor harmful effects. No significant quantities of dust fractions capable of alveolar deposition or inspiration occurred during print runs on colour photocopiers and laser printers. The results of the measurement programme, which employed random sampling, provided no evidence of any particular hazard when colour laser printers and colour photocopiers were used properly. It is recommended however that such equipment be used only in well ventilated rooms, and be serviced regularly. It should be kept in mind when new equipment is purchased that toners can be changed with virtually no production of dust by means of state-of-the-art technical device. The members of the BG expert committee in the administrative sector are now using the experience gained by the BG Institute for Occupational Safety - BIA to draw up test principles for the assessment of laser printers and photocopiers. These principles will be added to the catalogue of criteria for the issuing of the new BG "safe - ergonomic - low-emission" quality seal.

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