3D printing may be the wave of the future, but a new study from the Illinois Institute of Technology claims the machines could be harmful to human health. The resulting paper says the heating of plastic associated with 3D printing releases “harmful nanosized particles” similar to an industrial operation. Professor Brent Stephens and his team with the Illinois Institute of Technology measured the ultra-fine particles, or UFPs, put off by printers in an office space during normal operation. The team also compared two types of plastic extruded to create the 3D images and equated both to either burring a scented candle or a cigarette. The study is now published in the journal Atmospheric Environment and is the first to measure airborne particles released from commercially available printers. Inventors, creators, engineers and more have turned to 3D printers like the MakerBot Replicator to produce tangible, plastic prototypes which begin as a CAD model. Though there are different brands available, they each generally work the same. Two types of plastic are heated and then extruded through a nozzle to create layers. As the printer head moves, the shape is formed. Stephens, an assistant professor with Built Environment Research Group in the Department of Civil, Architectural and Environmental Engineering at Illinois Institute of Technology, measured the amount of UFPs being released in the air while these machines were running. UFPs are defined as small particles which are less than 100 nanometers in diameter and, according to the study, the air samples were taken during normal operations in an office space. Total measurements of UFP were spread between PLA material and ABS material, the two types of plastic used in printing. PLA (or polylactic acid feedstock) melts at a lower temperature and released about 20 billion particles per minute when used to create prototypes and other plastic parts. The second material, acrylonitrile butadiene styrene (ABS), melts at a higher temperature and releases as many as 200 billion particles per minute during normal operation. Stephens says these emissions are similar to those released by candles, cigarettes and even gas or electric stoves. ABS and PLA are the two types of material available for use in the MakerBot Replicator 2 and, according to VentureBeat, those who use these printers are familiar with the two different smells produced from the high and low temperature feedstock. The hotter running ABS is said to put off an offensive and even punishing smell while the cooler PLA reportedly smells like honey and sweet waffles. Regardless of smell, UFPs have been found to make their way into the lungs and air pathways in the head where they can build up and make their way into the brain. Additionally, as UFPs have high amounts of surface area, they’re capable of picking up concentrations of other compounds. Recent studies have shown, if taken in high enough concentrations, inhalation of UFPs could lead to asthma, stroke and even deadly heart attacks or lung issues. Just as they range in the amount of UFPs produced, the two types of plastic also range in their toxicity. For example, the UFPs produced from ABS plastic has been found to be harmful to laboratory mice and rats. On the other hand, PLA has been found to be safe for human use, as these nanoparticles are often used in drug manufacturing. Stephens and his team suggest using 3D printers with proper filtration and ventilation to reduce the possible negative side effects of breathing the plastic UFPs.