Are Laser Printers Safe?

A study by Congrong He, Lidia Morawska, and Len Taplin in Environmental Science & Technology titled "Particle Emission Characteristics of Office Printers" raises questions about the safety of laser printers.

Here's an excerpt from a related Environmental Science & Technology news article:

When researchers in Australia discovered that particulate matter levels were five times higher during the workday inside a nonsmoking office building than outside near a freeway, they looked for indoor culprits. After testing more than 50 printers throughout the building, they found that particle emissions varied depending on the type and age of the printer. In one case, standing near a working printer was much like standing next to a cigarette smoker.

Here's an excerpt from a related Scientific American article:

When the researchers investigated emissions from all 62 printers in the entire six-story building, they found that 25 of them (40 percent) were emitting particles. Among those, 17 (27 percent) were "high emitters" (including HP LaserJet and HP Color LaserJet models, and one Toshiba Studio model), which caused the concentration of particles in the surrounding air to jump tenfold when just one page was printed. The majority of particles were ultrafine, or less than 0.1 micrometer in diameter.

"Because these particles are so small, there is a very high probability for these particles to deposit in the deepest alveoli in the lung. . .; from there they can enter the bloodstream," Morawska says. This could cause changes in blood properties that lead to cardiovascular disease, she notes. If the particles contain cancer-causing agents, exposure could also increase the risk of cancer, but Morawska says researchers did not test the chemical composition of the particles. The primary purpose of this study was to determine the concentration of ultrafine particles emitted by laser printers.

More coverage: "HP Dismisses Laser Printer Health Risks," "Is Your Printer Polluting the Air You Breathe?," "Printer Emissions as Bad as Cigarettes?," "Some Top Laser Printers Called Office Polluters," "Study: Laser Printers May Pose Health Risks," and "Warning: Laser Printers Could Be a Health Hazard."

Sources: He, Congrong, Lidia Morawska, and Len Taplin. "Particle Emission Characteristics of Office Printers." Environmental Science & Technology Articles ASAP, 1 August 2007; Lubick, Naomi. Printer Particle Emissions Add Up. Environmental Science & Technology: Science News, 1 August 2007.