3D printing is great fun. Printing useful household items makes it more fun. But while bringing different objects to life, including your kitchen utensils, there is a cause to wonder if it is safe for these 3D printed objects to come into contact with the foods and drinks we ingest, as well as the impact of fumes generated while printing these items. It is absolutely understandable if you have such concerns. At least, if these objects can contaminate your food or cause toxicity in any way, you should know about it.
This is about one of the materials used in 3D printing, ABS. Acrylonitrile butadiene styrene (ABS) is a common polymer of thermoplastic origin. Most children toys like Lego bricks, home appliances like vacuums are often produced with this material.
History has it that, it has been available as early as the 1940s. And it has since gained widespread use because of its desirable mechanical properties. ABS is known to be tough, strong and flexible and can easily be molded. However, concerns have been raised about its safety.
Health and safety of human users
Any time we burn stuff, it releases particles into the air. All extrusion type 3D printers emit vaporized organic compounds (VOCs) as well as Ultra Fine Particulates (UFPs) into the ambient air around them.
The general emissions we experience from 3D printing are extremely small. Too low to be considered a health risk in most circumstance.
With that said, there are some exceptions to this logic. While the UFPs of some materials are not always harmful, the VOCs ranges from acceptable for PLA, PETG and other co-polyesters, to downright awful with ABS.
As for resin printers, the liquid resin itself is well known to be toxic and can cause mild irritation when in contact with human skin. Though such resin may not be as potent as some laboratory grade hazards, it must be handled with utmost care. The liquid resin should always be handled with disposable chemical resistant gloves.
Additionally, resin 3D prints also need to be washed with a solvent and cured after printing. This further increases the requirement of providing resin-type printers with a safe, controllable environment away from children, pets or any other living organisms that could potentially cause a toxic spill over or a messy accident. Precautionary steps are given below.
Potential effects of ABS on the body
Researchers have concluded that many of the constituents of ABS in their isolate form are carcinogenic. This means that if these substances are ingested, it increases the chance of cancer formation.
Cancer is a type of disease in which the normal cells in the body become damaged and does not undergo a process called apoptosis, programmed cell death, a healthy system of balance within the body. With the slowdown of apoptosis, the cells divide and multiply, in a process called mitosis, faster than they die. Substances that increase the risk of cancer are called carcinogens.
Cancer is a very complex biological phenomenon and research topic. There are many factors that will determine the probability of the growth of cancer within the body. Factors that goes beyond the exposure to the here mentioned substances. Nevertheless, they may create terrible reactions once in body, cancerous or not.
It is not so much the contact with these potentially carcinogenic compounds, as much as it is the extent of the exposure to these substances. There is a quantifiable threshold at which the adverse effects from the contact with these compounds can reach a critical point, sometimes referred to as the infectious dose. That threshold is generally unknown however, which is why it is referred to as a statistical risk.
In extremely large quantities, these substances may have a direct impact on cellular metabolism. They may even cause the destruction of the DNA in cells directly and thus disrupt the biological processes leading to the formation of malignant tumors. Common cancer sites are breast, colon, lungs and others.
In a research that spanned many years conducted by Georgia Institute of Technology and UL Chemical Safety, they established that 3D printing indoors using materials like ABS can contaminate the quality of air in a house.
The published findings demonstrate how the printers emit particles in a controlled environment. They discovered that different sizes of these particles are emitted including inhalable sizes which can find its way into the pulmonary systems of humans which can cause adverse effects.
Research further proved that more than 200 volatile organic compounds are released when 3D printers are printing using ABS. These compounds are considered carcinogenic and can cause irritations.
Melting temperature of ABS and its effects
The factor said to contribute to this the most is the nozzle temperature and the overall temperature at which the plastic is melted. Considering the type of materials used, and the temperature at which it melts. It was also established that ABS plastic produces more particles than one of its counterparts, PLA plastic, because ABS plastic filament has a higher melting temperature than PLA plastic filament.
ABS is stable after it has cooled and solidified. At higher temperatures during the melting and forming process however, it can decompose to the constituent substances that it is made up of.
ABS is a compound of three main substance: butadiene, which has been established to be a known carcinogen, styrene an organic compound, also a known carcinogen and acrylonitrile, a potential carcinogen.
How ABS fumes relate to tobacco smoke
It may surprise you to know that these constituent substances of ABS are also present in tobacco smoke, one of the leading causes of lung cancer. Tobacco smoke is a complex mixture of as many as 5,300 identified chemicals.
Some carcinogens in tobacco smoke have been identified by a method called the “Margin of Exposure” approach. Using this method, some of the identified carcinogenic compounds in tobacco smoke were, in order of importance, acrolein, formaldehyde, acrylonitrile, 1,3-butadiene, cadmium, acetaldehyde, ethylene oxide, and isoprene.
Most of these compounds can cause DNA damage by forming DNA adducts or by inducing other alterations in DNA. DNA damages are subject to error-prone DNA repair or can cause replication errors. Such errors in repair or replication can result in changes in tumor suppressor genes and this can lead to cancer.
Ultrafine Particles (UFPs)
Ultrafine particles (UFPs) are tiny particles invisible to naked eye which are produced and release into the air in activities such as cooking, cleaning and of course 3D printing. These particles are released even at low temperatures during the 3D printing process.
The UFPS themselves are not harmful beyond the typical sinus irritation and allergy flair up to those who are sensitive to sub optimal air composition. It is however the chemical deposit contained within the particle that is the concern. As with ABS, high concentrations of UFPs containing the nasty substances generated in the melting process is a definite cause for uneasiness.
According to a study in 2015 conducted by the Illinois Institute of Technology, desktop FDM 3D printers using ABS plastic are noted to be “high emitters” of ultrafine particles (UFPs). Excessive inhalation or ingestion of these particles can lead to negative effects.
ABS has been established to be the most hazardous, but it is still quite important to operate your 3D printer in a well-ventilated room regardless of the material being used. It is also a good idea to eat daily meals apart from a working 3D printer to prevent any cross contamination.
Research in this area is ongoing, but it’s reasonably certain that if you don’t want to breathe these particles, then you most likely won’t want to be eating food that contains them either.
Other indoor emitters
In a study published by the state of California, researcher aimed to gather a good understanding of the effects of indoor cooking on indoor air quality using both gas and electric stoves.
The study found an average concentration of particle matter ranging from 2.9 – 3,880 micrograms per cubic meter of air over several tests. The average of the results was greater than the U.S. National Ambient Air Quality Standard of 24-hour average of 65 micrograms per cubic meter of air.
Lung cancer, a risk of ultrafine particles (UFP)
Lung cancer (pulmonary carcinoma) is the most common cancer in the world, both in terms of cases (1.6 million cases; 12.7% of total cancer cases) and deaths (1.4 million deaths; 18.2% of total cancer deaths).
Lung cancer is largely caused by tobacco smoke. Risk estimates for lung cancer in the United States indicate that long term exposure to tobacco smoke is responsible for 90% of lung cancers.
Other factors are implicated in the formation of lung cancer, and these factors can interact synergistically with smoking so that total attributable risk adds up to more than 100%. These factors include occupational exposure to carcinogens (about 9-15%), radon (10%) and outdoor air pollution (1-2%).
Fumes from 3D printers using ABS plastic have been reported to cause irritations to the eye, skin and respiratory tracts. It can cause drowsiness, headaches and nausea.
Some cases of severe throat itching have been reported after long time exposure to fumes from printing using ABS filament. Also, feeling fatigued and severe headaches have also been attributed as a result of inhaling ABS fumes.
Some studies have shown that small amounts of chemicals from plastic containers can end up in the food or drinks that are kept inside them. But the levels of these are very low.
In some experiments, plastic bottles are heated to high temperatures for many hours. Even at temperatures as high as 140⁰F (60⁰C), levels of chemicals that move into food and drink are still very low.
They are usually far under levels that are considered unsafe. However if this adds up to daily exposure from other sources it can make a significant difference. Another possible source of exposing food and drinks to carcinogens is through microwaving food products in ABS plastics.
It has been established that ABS decompose at high temperatures. Well microwave heats food to very high temperature. There is therefore a small chance that the constituent substance may break down and leach into the food being heated. Not very likely but possible. This can cause exposure to a dangerous amount of these toxic substances.
ABS filament is neither biodegradable nor made from renewable resources. The 3D prints can be recycled (the recycling code “#7”) but doing this consume a lot of energy and produce waste materials. If you care about the environment, you may want to consider other alternatives to ABS filament.
Risks: Stomach cancer, colon cancer etc.
Diet is a major factor in gastric cancer and other types of cancer. Ingesting carcinogenic substances can attribute to this risk. However getting cancer depends on more factors than just ingesting carcinogens and this also depends on how much of it was consumed and how often and so on.
Precautionary actions you can take
In any case, it is obviously better to breath cleaner air then dirty air. Whether the contamination is with harmful or harmless substances. We recommend a few things you can do at home to reduce the impact on air quality when operating 3D printers:
Use your printer in a well-ventilated room or outdoor. Good ventilation reduces your contact with these potentially poisonous fumes.
You should keep a distance from the printer when not giving instructions to it. This protects your skin and eyes from irritation. Also, use safer materials that have low emissions.
Moreover, using the lowest possible temperature is advised. However, the temperature should not be lower than permitted so as to get the job done. This is because emissions increase with temperature. You can as well get a protective filtering system. Remember safety comes first.
If ABS and other 3D printing emissions is something you worry about, consider buying an enclosed 3D printer with a built-in filtration system. You can also build you own filtration system or purchase one as an aftermarket accessory. The best filtration media in this case will probably be activate charcoal. See list of required personal safety equipment in, Every 3D printing tool you will ever need – from beginner to pro.
Furthermore, avoid using ABS plastics for food processes that require heat such as microwaving, or even storing food item for a long period. It is better to use glassware or stainless for such purposes.
Also, do not wash an ABS plastic container in a dish washer because the high temperature can cause it to decompose and cause contamination.
Another important thing to note is that ABS plastics have poor chemical resistance to solvents like alcohol. Therefore, you should not use 3D printed mugs or beverage containers printed with ABS plastic material to drink or store alcoholic beverage. Otherwise you risk ingesting chemicals.
For a look at the research studies cited in this article, see the following references:
- Study by the group from Georgia Institute of Technology on the Composition and Toxicity of Particles Emitted from Consumer-Level 3D Printer published by the American Chemical Society.
- The study conducted by the Illinois Institute of Technology on Ultrafine particle emissions from desktop 3D printers published by Science Direct.
- The study by State of California on the effects of cooking on indoor air quality.