From JEMS Editor-in-Chief, A.J. Heightman: The results of a study, Particle emission characteristics of office printers, published in the American Chemical Society's Environmental Science and Technology journal has applicability to EMS/Fire rescuers for any incident. While more research has to be conducted as to the health effects of laser printers, it's worth noting that there were THOUSANDS of them that were in the World Trade Center and disintegrated and their contents dispersed throughout the breathable air when the towers collapsed.
For more on the study, check out FoxNews
For Hewlett-Packard s response, check out ComputerWorld.com