A new study sheds light on the potential health costs of 3D printing.

There’s little room for debate around the merits of 3D printing. That’s reflected in their growing use in homes, schools, and other settings where people spend a lot of time. But a new paper comes to warn that the printers aren’t harmless. The printing process can affect air quality and public health through the airborne particles it generates — these are small enough to enter deep into the lungs, the authors warn.

Printing problems

“To date, the general public has little awareness of possible exposures to 3D printer emissions,” states Peter Byrley, Ph.D., EPA, lead author.

“A potential societal benefit of this research is to increase public awareness of 3D printer emissions, and of the possibly higher susceptibility of children”.

Such printers have served an invaluable role during the pandemic, when institutions as well as individuals turned to them for face shields, respirator parts, or other equipment needed (but scarce) in face of COVID-19. However, the authors argue that it’s precisely due this rise in use that we should understand the health effects of 3D printing.

Materials used in the printing process can vary greatly, depending on the model, and include thermoplastics, metals, nanomaterials, polymers, or volatile and semi-volatile organic compounds. Each print can take up to several hours to complete (depending on the printer and the size of the item). During this time, a wide range of chemical by-products and particles can seep into the environment, especially indoors, according to the authors.

The paper provides a meta-analysis of existing literature on the subject. The team reports finding evidence that ABS (acrylonitrile butadiene styrene) emissions generated during the printing process can affect human and rat lung cells it comes into contact with. The same study showed that these particles cause “moderate” toxicity in human lung cells and “minimal” toxicity in rats. Two recent studies from the EPA also showed that emissions from a 3D printer filament extruder (a device used to create printer filaments), both vapor and small particles, are similar to those found in the ABS study. They also report that these emissions can lead to deposition of particles in the lung tissues of individuals aged nine and younger (based on computer simulations).

Another cited study examines the ecological cost of 3D printing. The accessibility, convenience, and scale of 3D printing today is a direct contributor to plastic pollution, it explains. Nanoparticles generated from the breakdown of 3D printed materials were further found to become biologically available when exposed to the environment (meaning an animal or plant can absorb them into their tissues). It establishes a Matrix Release Factor (MRF), describing the percentage of nanoparticles that came out of the plastic when eaten by fish, which can help us gauge how much of them are released when a product breaks down or is consumed.

“This research can help set regulations on how much nanomaterial fillers can be added to particular consumer products, based on their MRF value,” states Sipe. “The data can help determine how much plastic and/or nano-filled products release contaminants into the environment or the human body.”

These risks are manageable, but the only way we can protect ourselves is to know they exist. The authors are confident that 3D printing will continue to enjoy wider popularity in the future, so more in-depth research is needed to uncover all sides of the story in order to make the most of it while keeping people and the environment healthy and safe.

The findings will be presented at the Society for Risk Analysis 2020 Annual Meeting.