March 11, 2021

The Latest Research on FDM 3D Printing Risks

Summary: 3D FDM printing creates UFPs (ultrafine particles) that are breathed in and can create inflammation and other risks. It can also let off VOCs (volatile organic compounds) that can be toxic. PLA is overall a safer material to print with, but still does let off UFPs and VOCs and could be dangerous, especially to children. ABS lets off much more UFPs and more dangerous VOCs and has been observed to create health problems for those who use it frequently. Other plastics usually fall somewhere in between when it comes to health risks. Because of these risks, it’s important to consider the safety of how you 3D print. An enclosure with a ventilation system is an effective way to help combat the potential risks of 3D printing.

There are a lot of opinions online about what is or isn’t safe when it comes to 3D printing. But what does the research say? A brand new review that combined findings of 100 different studies on FDM 3D printer safety came out at the end of 2020 [1]. It summarizes the most important data we know about 3D printing. So what did it say?

Why can 3D printing be dangerous?

First off, to understand the risks, we have to look at what happens when you use fusion deposition modeling (FDM) to 3D print a material. The 3D printer heats plastic filament at or above its melting point and then lays it in the proper position to create the desired print. When you heat plastics this way, it can release ultra-fine particles (UFPs) and volatile organic compounds (VOCs). The review said that these two things are the “emissions of major concern” [1].

So what are UFPs?

Ultra-fine particles are generally defined as particles that are smaller than 0.1 micron, which is 1000 times smaller than the width of a human hair. They are often discussed when talking about air pollution, and are noted to be dangerous. An article by Durham Environment Watch stated, “Studies have shown that ultrafine particles are more toxic than larger particles…. [and] have been shown to be capable of inducing inflammation and oxidative stress.” [2]. They are dangerous because they are so small, which allows them to get deep inside your lungs and even absorb into the bloodstream. One example of their ability to get deep into your body tissues is one study in 2015 found that UFPs from air pollution was associated with heart disease (note, this was UFPs related to air pollution, not 3D printing; there have been no studies about 3D printer UFPs and heart disease) [3].

And what about VOCs?

The US Environmental Protection Agency (EPA) explained it this way: “Volatile organic compounds (VOCs) are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects…. VOCs are emitted by a wide array of products...includ[ing]: paints and lacquers, paint strippers, cleaning supplies, pesticides, building materials and furnishings, office equipment such as copiers and printers, correction fluids and carbonless copy paper, graphics and craft materials including glues and adhesives, permanent markers, and photographic solutions” [4]. They also say that “studies indicate that while people are using products containing organic chemicals, they can expose themselves and others to very high pollutant levels, and elevated concentrations can persist in the air long after the activity is completed” [4].

One study found that 3D printing can create 216 different kinds of VOCs [5]. However, the amount and danger of these VOCs and the UFPs mentioned earlier depends on many factors. Let’s start by looking at filament type.

PLA is a safer material, but it still emits UFPs (particles that can get into your lungs and bloodstream) and VOCs (chemicals that can be harmful), and we don't yet know its long-term effects.

PLA: Safe(ish?)

The most commonly used printing material is polylactic acid (PLA), which is generally considered to be safer than other materials, especially when talking about the types of VOCs it emits. The researchers noted that “Many speciated PLA-based VOC emissions are not harmful and within trace levels” and confirm that PLA is much safer than other printing materials, especially ABS [1].

However, PLA still releases VOCs and UFPs. PLA released 20 billion particles per minute, which is lower than ABS (200 billion particles per minute), perhaps somewhat due to higher heating temperatures of ABS. However, one study found that “the average size of PLA emitted particles was lower than ABS and therefore they had higher chances of entering into cells, leading to more cell damage” [1, 6]. UFPs can be aggravating to the respiratory system, especially for those who have asthma or other respiratory issues. However, they did note that because the number of PLA particles was so much lower, it still presented less overall risk than ABS.

Both PLA and ABS emitted particles that were toxic to in-mice and in vitro cellular assays. (But note that this was only when PLA was emitted in higher relative doses.) So while PLA is safer, if you use it frequently or over a longer period of time, there may be some adverse health effects. There has yet to be any long-term studies on the effects that regular 3D printing can have on general health over a lifetime.

Another important thing to note is that PLA can especially be of concern when used around children. “Toxic fumes known as VOCs may also be released not only by ABS but also by PLA. It emits VOCs which are particularly toxic to children” [1, 7]. Some studies have been done on 3D printer toys, which use similar technology to regular 3D printers. When used in an indoor setting, especially with multiple toys at once, “the maximum levels measured are high enough to induce acute skin, lungs, and irritation effects on eyes. Prolonged exposure could be indicative of more severe health effects” [1, 8].

Overall, PLA is still the safest option as far as filament type goes. However, the dangers are still being investigated, and because 3D printing is still relatively new, we have yet to understand any possible long-term effects on 3D printer users.

ABS: Not your BFF

ABS is often known as a more dangerous plastic to print with. But just how bad is it? First, as noted above, ABS releases 10 times more UFPs than PLA, which can be aggravating to the respiratory system. Many individual users have reported respiratory problems when using ABS, especially those who have a history of asthma or other lung issues. In a survey of employees who regularly operated 3D printers with ABS, 59% said they had respiratory symptoms at least once a week, and they were more likely to be diagnosed with asthma or allergic rhinitis [1, 9].

In addition to simply releasing more UFPs than PLA, ABS releases more harmful toxins. Studies with mice and rats have shown that ABS fumes are harmful to their health. Among other toxic chemicals, styrene is of particular concern. Styrene accounted for more than 50% of total VOCs emitted in one study [10]. Styrene is a known as a toxic chemical and the EPA notes that styrene can cause problems such as eye irritation, headache, fatigue, and other effects on the central nervous systems. Several studies link styrene to an increased risk of cancer [11].

So in short, ABS can be quite dangerous to print with and those who print with it should take care to ensure their safety.

Other plastics: (Usually) In between

Other studies have looked into many different types of filament. Plastics like Nylon, PETG, etc. are usually somewhere in between PLA and ABS when it comes to 3D printer safety. An exception is PCABS, a variant of ABS, which emits more particles and significantly more VOCs (and more harmful ones) than ABS [12].

One study found that Nylon was between PLA and ABS when it came to the number of UFPs emitted, although the particles emitted from Nylon were larger than either PLA or ABS [13]. Nylon also emitted caprolactam, a substance that the EPA says can cause “irritation and burning of the eyes, nose, throat,” People who are exposed to this have also reported “headaches, malaise, confusion, and nervous irritation” (although long-term exposure has not been shown to involve other effects besides “peeling of the hands and some eye, nose, and throat irritation”) [14, 15]. In other words, it may be more harmful than PLA, but does not seem to be as risky as ABS.

PETG had particle emissions in between ABS and PLA but less VOCs. (One of these VOCs was benzaldehyde, which is a hazardous substance, but it was emitted at extremely low rates) [12].

ABS can be very toxic because it emits high levels of UFPs along with dangerous VOCs. Other plastics also carry risks.

Other factors: Temperature, Brand, Age, Usage

Print temperature has been consistently shown to have a large impact on the emissions of 3D printers. Higher temperatures create more UFPs and higher concentrations of VOCs. For example, the fact that PLA is usually heated only to lower temperatures (when compared to ABS) is one reason why ABS is often found to be more dangerous. The higher you heat your PLA, the more dangerous it could become. The researchers suggested that you should use the lowest possible temperature for any type of filament used.

Filament brand, printer brand, and filament color can also have an impact on the levels of emissions. While different studies show different factors as being more or less important, printer brand and filament brand seem to have a higher impact on emissions than color.

Printer age may also be a factor. One study’s data suggested (although not conclusively showed) that the 3D printer’s age can impact emissions, with toxins rising with the age and use of the printer [1, 10].

Where and how often you use your printer is also important. Someone who uses their printer a few times a year and keeps it in a garage with good ventilation does not likely need to worry about health risks. However, someone who regularly uses a printer in their bedroom or office could be placing themselves and others around them at risk.

How to keep printing safely

We, along with many other 3D printer owners, still love 3D printing and don’t plan to stop anytime soon. There are a number of routes you can take to ensure that you can still 3D print safely. First, use PLA instead of ABS or other plastics when possible. You can keep your 3D printer in a garage (unless you are often working in the garage and don’t ventilate it well) or try to ventilate wherever you do have the printer. In addition, studies have noted that some air filters can get rid of UFPs quite effectively. One study found that HEPA filters seem to be the most effective, although notably HEPA filters do not help with VOCs, only UFPs [1, 16]. You would need an activated carbon filter to help filter VOCs.

We think the above options are all less than ideal--sometimes ABS or other high-grade plastics are desirable, not everyone has a well-ventilated garage or wants to keep their 3D printer there, and it requires a powerful filter and fan system to make sure you are ventilating the room well enough. Filters also need to be high-quality and running well to actually keep you safe, and it can be a hassle (and costly over the long-term) to constantly replace air filters. That’s why we recommend getting an enclosure with a ventilation system.

Our Boxomo Enclosures are designed specifically for optimal safety--if you use our enclosure with a ventilation kit, the fan keeps negative pressure inside the enclosure, which sucks the air out through the ventilation duct. The duct can be placed out through a window If a window is not available, you could rig it to vent out through an air filter. Note that a HEPA filter and activated carbon filter combination is recommended to help remove both UFPs and VOCs.

An enclosure also has other benefits, such as keeping your printer clean and allowing for better heat regulation, which is key to getting good prints in ABS, Nylon, and other materials.

Image taken from Figure S5 "Variation in the number concentration of nanoparticles over time during 3D printing for all control methods" [16]. Enclosures can help mitigate 3D printing risks.

We have rigorously tested our 3D printers to ensure that the system works well, and we use our 3D printers with much more peace of mind knowing that we are keeping ourselves free from any potential health risks.

While everyone has different opinions, we do want people to understand that there can be real risks to 3D printing. Any 3D printer user should look into the research, consider their circumstances, and decide what is needed to protect their health. We hope you reach out to us with any questions you have, and that you continue to enjoy your 3D printing safely!