How Toxic is 3D Printing? UL Research Sheds Light

The Chemical Insights Research Institute of UL Research has released a new study seeking to shed light on the nature of volatile organic compound (VOC) and particle emissions during the process of fused filament fabrication (FFF) 3D printing. If you’ve perused 3D printing forums long enough, you’re sure to have encountered heated back-and-forths about the suitability of 3D printers in home and office environments.

To the surprise of no one: the answer is complicated. However, before we jump into the outcome of the research, let’s add a little context to how this study was conducted. UL’s model considered a “worst-case scenario personal exposure” to be approximately 1 meter (3 ft) from an operating 3D printer. In simulated, non-industrial environments, the researchers assumed that the printer was the sole source of emissions. More on that context later. Let’s explore what this study found.

What Makes FFF 3D Printing Toxic?

While FFF print conditions play a pivotal role in influencing emissions, filament material emerges as a major factor. Different materials require distinct optimal printing setups. ABS, nylon, and HIPS filaments consistently stood out with the highest particle number emission rates, while metal and PLA filaments followed suit. Formaldehyde was among the top 5 most abundant VOCs for 7 out of 9 materials studied.

Metal composite filaments displayed larger particle sizes and higher mass emission rates, hinting at the distinct emission behavior of these materials compared to pure polymer filaments. Total volatile organic compound (TVOC) emission rates varied across different filament materials, with ASA, PETG, ABS, and some nylon filaments emerging as high emitters. Conversely, metal composite filaments exhibited lower TVOC emissions, likely attributed to their high metal content. The top five most abundant VOCs emitted were associated with the main polymer material of the filament, providing insights into the specific chemicals released during the printing process.

Chemicals of concern detected from at least five out of nine filament materials with detection frequency (%) shown in heatmap

The study notes, however, that it was difficult to correlate particle and VOC emissions, with low to no correlation observed overall. The paper also notes that there is a wide variation in emissions within particular material types. Manufacturer-specific formulations and additives emerged as potential contributors to high emission levels of certain VOCs, regardless of other print conditions.

While ABS and HIPS materials generated the highest exposure concentration, PLA, PETG and PVA, showed lower comparable median exposure concentrations. The levels released were comparable to (but sometimes higher) than typical ultrafine particle levels found in homes, offices, and schools. The study goes on to suggest that personal exposure to FFF emissions is similar to indoor activities such as cooking on a gas stove.

Even though the study assumed an environment where the printer is the sole source of emissions, in the real world everything from our stoves to our air conditioners is a source of emissions at play in our home and office environments. These conditions could naturally lead to spaces with higher-than-recommended concentrations of particles. The flow of air in and out of a room also plays a crucial role in all of this as well.

The biggest takeaways from the paper’s conclusions were:

• Avoid using high emitting materials such as those with styrene monomer
• Avoid operating the printer in confined spaces or with limited ventilation.

To dive into the paper’s conclusions yourself, check them out at here at Science Direct.