Just when you thought it was safe to hang out in the office, scientists are now reporting that some laser printers are as harmful to your lungs as second-hand smoke. Certain models of the printers emit high levels of ultra-fine particles that can cause irritation of the airways and possibly even heart disease and cancer.

The study touches on a larger and mostly overlooked health concern: indoor air pollution. Most people spend 90 percent of their lives inside—a frightening statistic—yet indoor pollution isn’t monitored. Sure, we’ve booted smokers to the curb, but that hardly helps if we’re all still breathing in microscopic bits of toner dust.

Still, not every printer is guilty. More than half of the 62 models tested were non-emitters. But the researchers classified 13 as high polluters. The study’s authors actually say that some models produce so much pollution that sitting near one would be the equivalent of having your next door neighbor in cubicle land puffing away on cigarettes.—Gregory Mone