A modified version of PET material used in packaging, PETG is generally considered a safe thermoplastic. Once printed and cooled, PETG parts become food-grade approved and can be used for a wide range of applications.
However, there is more to it than it seems.
PETG is toxic during the printing process. PETG fumes contain organic volatile compounds (VOCs) that pose a health risk if inhaled. Plastic nanoparticles released while the material is melted are also harmful. This is one of the reasons why PETG should be printed in an enclosure.
Despite its potential toxicity, however, PETG is generally considered safe to handle. It is less toxic than ABS and, when printed according to instructions, doesn’t raise any major health concerns.
Toxicity Of PETG
Like all thermoplastics, PETG can become toxic with improper use.
While the material is typically considered safe, here are a few things to keep in mind if this is your go-to filament.
Fumes and Off-Gassing
The greatest risk when printing with PETG – and any other thermoplastic, as a matter of fact – is that of inhaling toxic fumes and off-gasses.
Off-gassing refers to a material’s capacity to trap a harmful gas and release it due to sublimation or evaporation, and is different from the potentially toxic fumes released by plastic materials as they are melted. PETG can release both types of toxic vapors.
D-limonene and acetic acid are two of the main substances released by PETG during printing. Neither is particularly dangerous, but both of them can be responsible for a series of undesired symptoms in humans.
For instance, D-limonene is considered an allergen that can cause contact dermatitis in sensitive individuals.
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In its vapor form, acetic acid is a severe irritant for the eyes, skin, mucous membranes, and the upper respiratory tract.
Other VOCs released by PETG include aldehydes and styrene. These substances, too, can have irritating effects on the upper respiratory tract, skin, and eyes.
Thermal Decomposition
Another problem with PETG during printing is thermal decomposition, which can happen if the printing temperature is too high.
Beyond fumes, thermal decomposition leads to the release of nanoparticles that are small enough to pass through the upper respiratory tract and reach the lungs.
Microplastics have a harmful effect on the body, leading to a variety of health issues that can go from inflammation and infections to cancer.
Harmful Chemicals
In addition to all the fumes and microplastics, some PETG filaments can also release other harmful chemicals. This is often the case of poor-quality PETG colored with toxic dyes or with enhanced formulas created with toxic chemicals.
The worst part is that these toxic additives can be found in filaments that are otherwise FDA-approved. This is why you should only print with high-quality PETG bought from trustworthy brands. A few names include Hatchbox and Prusa.
7 Safety Measures For Handling PETG
Despite the chemicals that PETG can release, this material is not generally considered harmful.
These safety precautions should help you print PETG without worries.
1. Use Quality Filament
As mentioned, PETG is generally considered a safe material. Its fumes can be bothersome, but are typically safe to inhale for short periods. However, the toxicity degree increases in the case of poor-quality filament.
If you want to stay on the safe side, you should use quality filament only. Hatchbox, Polymaker, and Prusa are three of the best-rated brands.
Aside from the brand, you should also know that certain dyes increase the risk of toxicity. This is often the case with glow-in-the-dark products and metallic colors.
Thus, if you’re concerned about the material’s safety, you should probably stick to clear or white filament.
2. Use an Enclosure
Regardless of the type of filament you’re using, a sure way to prevent inhaling toxic fumes is by using a printer enclosure.
Printer enclosures are ventilated chambers that can either filter out VOCs and nanoparticles – through the use of activated carbon filters – or that are connected to an outside vent, expelling the fumes out of your home or office.
The enclosure size and filtration method can vary based on the size of your printer.
Desktop enclosures are ideal for desktop printers, but these models typically use an activated carbon filter. This should be enough for PETG, but if you want to use a specialty PETG type or have a large printer, you could invest in a vented enclosure
3. Maintain Proper Ventilation
If you don’t have an enclosure and can’t get one for a reason or another, maintaining proper ventilation is key to preventing the accumulation of toxic fumes.
However, keep in mind that PETG is difficult to print in environments with air currents.
Ideally, you should place the printer in a dedicated room, away from open doors and windows. An indoor vent, similar to those used in bathrooms, should be enough to get rid of the fumes.
4. Adjust Printing Temperature
The main factor that affects PETG’s toxicity is the printing temperature. To prevent thermal decomposition, you should maintain the temperature under 255°C.
There are few filaments that require a higher temperature, and most desktop printers can’t go over 250°C, to begin with. However, if you’re using an industrial printer, it might be worth double-checking the settings before printing.
Sometimes, miscommunication between the slicer and printer could prevent the proper calibration of the hardware, resulting in an improper temperature.
5. Maintain Your Printer
Another thing to consider is printer maintenance, especially if you’re using a printer that can reach high temperatures.
Calibrate the printer periodically and run tests to ensure proper functioning. Hot end malfunctions could result in the nozzle reaching temperatures higher than the expected ones, which could consequently lead to thermal decomposition and the release of toxic fumes.
If you suspect a malfunction, have the printer serviced immediately – overheating poses a serious fire hazard.
Overheating signs include oozing, stringing, blobbing, and filament losing its properties, resulting in print defects.
6. Wear Protective Equipment
Another way to prevent inhaling toxic fumes is by wearing protective equipment. If you’re sensitive to chemicals, wear gloves when handling PETG, especially when manipulating a print that is still warm (you should ideally leave the part to cool completely on the build plate before handling it).
Goggles and a respirator can prevent eye and upper respiratory tract irritation. If you have a hypersensitivity to chemicals, you should also wear long sleeves to prevent contact dermatitis.
7. Store Filament Safely
Lastly, remember that PETG filament that isn’t stored properly can degrade and is more likely to release toxic fumes.
PETG should be stored in a cool, dry place. Avoid keeping it in a sunny spot, as UV radiation could degrade the material.
The best way to store PETG is in a filament box or in an airtight bag, with a few packets of silica gel to absorb moisture.
Also keep in mind that this filament type is highly hygroscopic. Moisture trapped inside the filament can lead to printing defects, so you should always dry the material before printing.
Aside from printing defects, trapped water could increase the risk of off-gassing while printing with PETG.
Frequently Asked Questions
Is PETG less toxic than PLA?
No, PETG is not less toxic than PLA. In fact, the contrary is true.
PLA is a biodegradable material derived from natural sources (renewable, fermented plant starch). While this starch is made into a sort of thermoplastic, PLA is less likely to emit VOCs or other chemicals while printed.
That said, both PLA and PETG are FDA-approved materials that are considered safe to print. Their fumes are generally not considered toxic.
What filament is body safe?
PLA, PEEK, PETG, and TPU are biocompatible materials that can be used for printing implants and other medical devices.
Conclusion
PETG is a safe filament with low toxicity. It is FDA-approved and safe to use for printing kitchen utensils, containers, and other food-grade items. The material is also biocompatible and safe to use for making implants and other medical devices.
However, this filament could release toxic fumes, especially if it is of poor quality or printed at a too high temperature.
To prevent these problems, you should only use high-quality filament, ensure proper ventilation, use a printer enclosure, and wear protective equipment.
