I've long heard rumors that the fine particulate dust used in laser printer toner cartridges may be a health risk. It certainly makes sense: Not all of that stuff can stick to the paper, and if you've ever spilled toner you know there's no way it can be good for your lungs. Now a controlled study is confirming the information, saying that 30 percent of all laser printers tested emit dangerous particles described as "causing lasting damage on the scale of inhaled cigarette smoke." These tiny particles lodge deep in the lungs and can lead to anything from lung irritation to full-on cancer.

The tests come from an Australian technology university and were conducted in a "large open-plan space," and found that printers could increase particulate matter in the air by up to 400 percent.

While I'm still trying to obtain the list of high vs. low particle emitters from the university, there appears to be a lot of variability among machines and even among different toner cartridges. New cartridges, for example, produce more particle matter than old ones. Printing graphics pages also produces more particle matter than text, since more toner is used, and obviously, air quality gets worse the more pages you spit out. I'll post the full list of printers tested here (or a link to it) as soon as I can obtain one.

The upshot is that printer emissions should potentially be regulated much the way that auto emissions are, but even in the absence of government intervention, use common sense around your printer: Limit use when possible (tell the guy that prints out every single email to cut it out), sequester printers in their own rooms and away from workers, ventilate offices appropriately, and have your own air and printer tested before it becomes a serious health problem.

UPDATE: The full study is available online now (scroll down to Table 1, at the bottom, for the list of printers tested). HP LaserJets (the vast majority of the models tested were HPs) appear among both the best and worst on the list. Check it out!

LINK: Printers pose health risks: study 

UPDATE: HP responds here