Several new studies have found that 3D printers emit toxic particles that can be harmful to humans.
The studies, presented at the 2020 Society for Hazard Analysis virtual Annual Meeting on December 15, showed that particulates released during the printing process can affect indoor air quality and public health.
For the uninitiated, 3D printers typically work by melting down plastic filaments or other basic materials like nanoparticles, metals, thermoplastics, etc. and then stacking the molten materials layer upon layer to form an object. When plastic or other base materials are heated to melt, they release volatile compounds into the air near the printer and the object.
Chemical by-products and particles released into the environment during the printing process can build up the later in the process and some are small enough to infiltrate the lungs and cause damage.
The studies presented today at the meeting looked at various types of emissions and how big the risk is.
For example, two of the Environmental Protection Agency (EPA) studies looked at emissions from a 3D printer filament extruder, a device used to create 3D printer filament, and then used a simulation model to see how many particles were released. they produced. such as where they were deposited when using a 3D printer in different age groups.
The studies found that the filament extruder released amounts of small particles and vapors similar to those found in other 3D printer studies, and the simulation model predicted higher particle mass deposition per surface area in the lungs for nine-year-olds. years or less. But more research is needed to determine what the inhaled dose would be.
Another of the featured studies, conducted by Yong Qian of the National Institute for Occupational Safety and Health, looked at the potential toxicity of acrylonitrile butadiene styrene (ABS) emissions generated during 3D printing by examining human and rat lung cells exposed by inhalation. . He revealed that the emitted particles cause moderate toxicity in human lung cells and minimal toxicity in rats.
It’s also worth noting that while much of this research presented today is still in its early stages, it adds to mounting evidence of the potential toxicity of 3D printers.
For example, research published last year found that both ABS and polylactic acid (PLA) particles negatively impacted cell viability, with the latter eliciting a more toxic response.
“Toxicity tests showed that PLA particles were more toxic than ABS particles on a per particle comparison, but because the printers were emitting so much more ABS, it’s the ABS emissions that end up being more of a concern,” he said. Rodney. Weber, a professor in Georgia Tech’s School of Earth and Atmospheric Sciences, who led the research. “Taken together, this evidence indicates that exposure to these filament particles could, over time, be as toxic as air in an urban environment polluted by vehicular or other emissions.”
The study also found that the higher the temperature required to melt the filament, the more emissions were produced, and the ABS particles emitted by 3D printers had different chemical characteristics than the ABS filament.
“When filament companies make a certain type of filament, they may add small percentages by mass of other compounds to achieve certain characteristics, but they mostly don’t disclose what those additives are,” Weber said. “Because these additives appear to affect the amount of emissions from ABS, and there can be great variability in the type and amount of additives added to ABS, a consumer can buy a given ABS filament and it could produce many more emissions than one. from a different provider.
This is important, especially as 3D printers become more common in homes, schools, and other places where people spend a significant amount of time.
“To date, the general public has little awareness of potential exposures to emissions from 3D printers,” said Peter Byrley, one of the lead authors of the EPA studies, in a statement. “A potential societal benefit of this research is to increase public awareness of 3D printer emissions and the potential increased susceptibility of children.”
And 3D printing might not only be harmful to humans, another study by Joana Marie Sipe of Duke University found that the by-products of printer-made plastics can also be harmful to the environment.
For the study, Sipe developed a machine that can measure how much a plastic product, such as a water bottle, can break down from rubbing and sanding during use and in the environment. The plastic particles were then fed to the fish to see what effects the plastic nanoparticles had on their organs.
What he discovered was that when plastics break down, the nanomaterials that were incorporated are exposed to the environment. The researchers were able to predict the percentage of nanoparticles that came out of the plastic when the fish ate them, providing a matrix release factor (MRF) that could be used to find out how much plastic and nanoparticles are released when a product is chewed or eaten. breaks down in the ocean.
“This research may help establish regulations on the amount of nanomaterial fillers that can be added to particular consumer products, based on their MRF value,” Sipe said in a statement. “The data can help determine how much plastic and/or nanofilled products release contaminants into the environment or into the human body.”
So while 3D printing makes numerous products more widely available and cheaper, as we’ve seen with the manufacture of face shields, respirators, and other Covid-19 personal protective equipment, it’s important to consider the potential risks. And as 3D printing technologies become more widespread, regulators, manufacturers and users may need to turn their attention to better managing those risks.
For example, some steps 3D printer operators can take to lessen their impact on air quality include:
- Operate 3D printers only in well-ventilated areas
- Nozzle temperature setting at the low end of the suggested temperature range for filament materials
- Stay away from running machines
- Using machines and filaments that have been tested and verified to have low emissions.