Some laser printers emit as much fine-particle pollution as cigarette smoke, which can lodge deep in people's lungs to pose a significant health threat, Australian researchers have found.
Some popular brand printers release so much toner into the air that the amount of fine particles in office air increases five-fold during work hours, and new toner cartridges and graphic-heavy printing projects further boost the amount of ultra-fine powder in the air.
In a study to be published on Wednesday, researchers from the Queensland University of Technology show that 17 of the 62 printers tested were "high particle emitters", sending an ultra fine powder that researchers - believed to be toner - into the air.
One of the printers tested released so many particles into the experimental chamber that it was akin to cigarette smoking, the report found.
Lead researcher Lidia Morawska said inhaling the particles could lead to respiratory irritation, and even more severe illnesses like cardiovascular problems and cancer.
Larger particles could also be unhealthy without reaching deep into the lungs, because they carry more toxins.
"No matter how you look at it, there could be problems," Dr. Morawska said.
Not all laser printers pose a health hazard, though. Thirty-seven of the 62 printers released no particles that diminished air quality, six released low levels, and two released medium levels.
The Canon, HP Color Laserjet, Ricoh and Toshiba printers - some of which are sold in Canada - were tested in an open office space in a multi-floor office building in Brisbane, Queensland. Three laser printers were tested in an experimental chamber.
The discovery was somewhat accidental, Dr. Morawska said.
"It wasn't an area that we consciously decided to study," she said. "We came across it by chance."
The research group had started studying the efficiency of ventilation systems in office settings, but soon found air pollution originating indoors from the laser printers.
The study, to be published in the online issue of the American Chemical Society's semi-monthly journal Environmental Science and Technology, found that indoor particle levels in office air increase five-fold during work hours thanks to printer use.
The scientists are now calling on Australian government officials to consider regulating emissions levels from laser printers.
HP LaserJet, Mita, Ricoh and Toshiba all had printers in the non-emission category.
Canon, HP and Ricoh had low-level emitters, while HP had the only two mid-level emitters.
The laser printers found to be high emitters, or potential high emitters depending on use, were:
HP Color LaserJet 4650dn
HP Color LaserJet 5550dtn
HP Color LaserJet 8550N
HP LaserJet 1320N
HP LaserJet 1320n
HP LaserJet 2420dn
HP LaserJet 4200dtn
HP LaserJet 4250n (old)
HP LaserJet 4250n (new)
HP LaserJet 5(a)
HP LaserJet 8000DN
HP LaserJet 8150N
Toshiba Studio 450