Is desktop 3D printing safe? Will it harm your health? The short answer, we don’t know yet. Always keep your 3D printer in a well ventilated room with ten or more air changes per hour. Today not enough consideration is given to possible harmful effects of 3D printing ABS and other materials in the home. New research is showing that potentially 3D printing could have harmful effects and we need to all take precautions to mitigate them.
Ultrafine Particle Emissions
An article on ScienceDirect looks into Ultrafine Particle Emissions from desktop 3D printers. The article concludes that,
“Estimates of emission rates of total UFPs were large, ranging from ∼2.0×1010 #/minute for a 3D printer utilizing a polylactic acid (PLA) feedstock to ∼1.9×1011 #/min for the same type of 3D printer utilizing a higher temperature acrylonitrile butadiene styrene (ABS) thermoplastic feedstock. Because most of these devices are currently sold as standalone devices without any exhaust ventilation or filtration accessories, results herein suggest caution should be used when operating in inadequately ventilated or unfiltered indoor environments. Additionally, these results suggest that more controlled experiments should be conducted to more fundamentally evaluate particle emissions from a wider arrange of desktop 3D printers.”
(EDIT: Added later after speaking with a friend, Ben McMillen I took another more critical look at the study. Thanks Ben!) The study was conducted at one location on one day. It was not repeated for any length of time or repeated during a series of days. It was also not conducted at many different locations. Environmental things such as an automobile parked near the location, smoke or other causes could have influenced the outcome. If the results were replicated in many locations it would be a much more significant finding. If in isolation several 3D printers would have been sealed in boxes and the resulting UFP concentrations would have been measured than it would also be more significant. If the experiment would have been done in more controlled locations and with many more readings over time then the results would also be more significant. In looking at the study it seems much more like an isolated finding that points to a possible issue than anything remotely certain.
I’m glad that research is being done into this area. Ultrafine Particle Emissions are nanoscale particles that may be inhaled by people and deposited in the lungs. With UFP inhalation there can be adverse health effects such as lung disease. I hope that more research will be conducted into this area and that suitable criteria for safe home 3D printing will be developed.
In addition to the UFP issue harmful fumes may be released. Indeed with regular melting/oxidation styrene, hydrogen cyanide and other harmful chemicals may be released when ABS is 3D printed. With regards to Hydrogen Cyanide some tests were conducted by individuals that concluded that the release of hydrogen cyanide was within limits, but no large scale research has been done. The fumes from the melting of ABS plastic have been known to cause adverse health effects in industrial workers exposed to processes such as injection molding. These workers do have considerable daily exposure much more so than one would ever expect to have when using a 3D printer in the home. But, the ”findings of this study implied the ABS plastic injection-molding process may worsen olfactory function among workers.” This pubmed artcile on carcinogens and respiratory sensitisers during the thermal processing in plastics concludes that in an industrial setting with controls in place there is very little to worry about. But, research on the effects of ABS fume build up in a consumer setting has not (to my knowledge) been done. Consumer 3D printers do not employ ventilation systems and are placed in many different types of rooms some with little ventilation. Likewise this 1995 article concludes that ABS(and other plastic’s)’ Thermal Decomposition Products produced “sensory irritation, coughing and airways constriction” in guinea pigs exposed to considerable levels of TDP. Based on this and other papers exposure limits for the workplace were set. But, again in a home setting the conditions will vary and one does not have HVAC and other countermeasures.
In my opinion to place a desktop 3D printer in a non ventilated or poorly ventilated room would be a risk that I personally would be unwilling to undertake.
Some 3D printers use resins containing Methacrylic Esters, these are a known skin irritant and may be cytotoxic. This article mentions “potentially cytotoxic acrylate based monomers.” While in this article, “the main drawback of these acrylate containing resins is the high cytotoxicity of residual unreacted acrylate groups.” Additionally in some cases detailed chemical analysis of photopolymers and SLA resins have shown that not all MSDS fully disclose all of the constituent ingredients of the material. This article looks at the photoinitiator contained in resins and concludes that “a clear toxic effect was observed with all tested concentrations, and a post-processing step of 7 days was required to leach out the initiator residues.” Especially with non fully cured parts some of these resins may produce risks, however the concentrations used in the study are far higher than found in the resins. The resins are known skin irritants however and users would have to make sure that they fully cured their parts in order to not have issues with that. With these resins safety precautions would seem to be very important and users must be very careful when touching parts made with them and residual material.
John Unwin’s Advice
John Unwin is the author of this paper as well as the Principal Scientist of Analytical Sciences Unit of the UK’s
Health and Safety Laboratory. and I asked him for his opinion on the safety of 3D printing.
“I am not aware of any issues that have been raised in HSE concerning this technology as far as exposure to fumes is concerned. However, the principles of good process control alluded to in my paper are equally valid in 3D printing I think. Temperature control of the polymer will be important because if degradation occurs due to overheating then its will affect the quality of the product. Catastrophic failure of the polymer (burning) would be required to produce degradation products of any acute concern. So I think it unlikely that there would be an appreciable build up of toxic fumes as the process would be terminated on product quality grounds. The printer should be regularly serviced and cleaned to ensure optimum performance In my research, all of the sites had a distinctive smell from the heating process. Even though the processes were well controlled and some of these processed up to 50000 tonnes per year, very little fume was observed and this was controlled with general ventilation or forced mechanical ventilation. Therefore I do not think there is a significant risk from polymers like ABS as long as the temperature of the process is adequately controlled. However as a precaution I would ensure an adequate number of air changes (6-10/hour) in the room or ensure that a build up of the annoying smell was avoided by opening a window and door to supply a reasonable flow of air at home.” (NB, Dr. Unwin’s advice here only concerns vapors, it does not cover Ultrafine Particle Emissions!)
With regards to both harmful fumes and ultrafine particle emissions not enough research has been done to without a doubt conclude that desktop 3D printing is completely safe. Fume hoods, HEPA boxes or respiration equipment may be the only way to reduce or eliminate UFP issues. Burning rather than regular melting of ABS would produce very harmful effects. With regards to fumes there is probably not “significant risk from polymers like ABS as long as the temperature of the process is adequately controlled.” Some materials such as resins are skin irritants and may cause additional harmful health effects. You must always use a 3D printer in a properly ventilated room with 10 air changes per hour. You should not smell any fumes from your printer during operation, if this is the case than this may be a sign that fumes are building up and could be potentially harmful. Always deploy safety precautions such as hoods or gloves when required. I would personally recommend that any and all desktop 3D printer users either make or purchase a HEPA box or fume hood to contain their 3D printer. The jury is not out yet on the UFP’s and there is much more research to be done but since this is your home and you are in proximity to this machine I would strongly advise that you do this.
Before we go all haywire on this. Lets ask us this question: is barbecuing safe? Many of the chemicals released while grilling are linked to increased risks of cancer. Barbecue smoke has carcinogenic substances in it. Additionally there may be issues with carbon monoxide and burns from the fire itself. Using accelerants and fire may cause additional health risks. If someone asked me, “Is barbecuing safe?” I would have to say that it was not. Yes millions of people continue to barbecue every day. We must not rush to conclusions or judge this amazing new technology too harshly. But, we must adopt the safety precautions that we know we need to.
It is amazing that 3D printing can give everyone a factory in their home. But, please do realize that yes this thing is a factory. And factories have lots of fumes, heat and possible hazards. 3D printers come with responsibility and are equipment not hereto found in the home. 3D printing is marching into the home at a pace that scientists and researchers concerned with safety can not keep pace with. Now research is being done for the first time and we must deploy the best methods to be safe at all times. Take care of yourself and do always realize that this amazing machine is a factory that happens to be in your house. Print safe out there everyone!