There is a lot of conflicting information out there about whether resin printing fumes are actually dangerous.

The cowboys on Facebook say it’s nothing to worry, while others on Reddit wear a hazmat suit just to clean their prints.

Below we summarise what research really shows, and what are the best practices to implement at home or in the workplace.

Types of emissions from a resin 3D printer

Researchers generally divide emissions into two categories: particulate matter (PM) and volatile organic compounds (VOC).

Particulate matter

Particulate matter is solid. They are like tiny specs of dust that get stuck in your lung if you breathe them in.

We are always subjected to some PM from things like smoke, cars and dirt.

PM levels are very low in resin printers, so we don’t really need to worry about them.

They are a bigger concern in FDM printers, so if you have one of those, you can check out this article to see how to deal with them. (Hint: it’s a HEPA filter).

Volatile organic compounds

Volatile organic compounds are gases. They are present in much higher concentrations in resin printers than in FDM.

In large doses or after prolonged exposure, VOCs are a potential health hazard.

Common sources are things like wet paint, household cleaners and permanent markers.

VOCs are also the things that make your resin smelly.

The famous “new car smell” is also a sign that toxic VOCs are being released into the air by the new plastic in your car. Ahh, delicious.

If you’re like me, your first thought was “great, I’ll just use less stinky resins!”

Unfortunately, it’s not that simple.

Some VOCs smell very bad even in small amounts, while others have no smell even in high concentrations. Different people are also sensitised to different chemicals, which changes how strongly we perceive them.

How dangerous are VOCs?

In the short term, VOCs can cause

• eye, nose, throat irritation
• headaches
• dizziness etc.

If you’ve been spending a lot of time around resin printers, you might have experienced some of these at one point or another.

Severe long-term exposure (eg. working at a chemical factory) can cause more serious side effects, such as

• allergy-like reactions, especially on the skin
• internal organ problems
• cancer

Some people are more susceptible to VOCs than others, especially those that have an underlying illness, like asthma.

VOC levels of up to 5000 µg/m³ are considered safe.

VOC measurements from a resin printing session. The peaks represent the start of printing, post-washing and post-curing stages

VOCs in resin printers

It is very important and reassuring that all of the studies we found recorded average VOC levels in resin printers that were well within the official safety levels prescribed by health organisations.

This is why there is generally no big health concern surrounding resin printer fumes.

At the same time, all researchers agreed that exposure must be limited as much as possible, and that more research is needed into the subject.

Another important note is that the conditions listed above are just generic known side effects associated with VOCs. Every resin emits a unique concoction of VOCs, and each mix would need to be studied over a long period of time before we could determine what their effect is on the human body. Given the vast variety of materials on the market, and the speed at which they are changed by manufacturers, it would be practically impossible to test all of them.

As such, the best advice we can give is:

Do not fear the fumes, but still limit your exposure as much as possible.

Heating your resin printer

We also learned that if you heat your resin printer (which you should, we wrote about it here), it increases the amount of VOCs released into the air by as much as 3 times. This effect has definitely not been studied enough, and might even put some printers above the recommended emission levels. 

How to limit your exposure to resin fumes

First, let’s define when you are exposed to VOCs. The touchpoints are

1. Print preparation
2. 3D Printing
3. Retrieving the print
4. Post-washing
5. Post-curing
6. Storage

By print preparation we refer to the activities directly relating to starting a new print: opening the printer door, pouring in new resin, mixing etc.

Preparing and retrieving the print represent an added level of danger, as you are directly exposed to quick bursts of VOC.

Post-processing also releases a heavy amount of fumes into the air, most of which come from the IPA used for cleaning.

Interestingly, in Yang et al’s tests, about 11% of VOCs were emitted not due to printing or post-processing, but just by the liquid resin being exposed to the open air.

Because of this, it would not be unreasonable to assume that storing unused resin in your vat for a long time could end up releasing more VOCs into the air than the printing process itself.

It is important to keep in mind all six of these stages as points of exposure. We created an infographic that you can download and print out, to help you remember them.

Now, let’s take a detailed look at what you can do to limit your exposure. We're going from most effective (elimination) to least effective (PPE) techniques.

I. Elimination techniques

Keep your printer in a separate space

Keeping your printer in a garage or workshop is one of the best ways to limit your exposure.

Large, well-ventilated rooms work best to keep the air fresh.

This will keep your living / working area free of fumes, both for yourself and your family.

Use water washable resin

An interesting finding from our research is that one of the biggest emissions of VOCs come from IPA.

These are emitted both during the post-wash and post-curing process in large amounts.

By using water washable resin, you can eliminate this hazard completely.

Remove unused resin from the vat

By pouring any unused resin back into its container, you can make sure that it will not keep releasing harmful VOCs into the open air.

Use a funnel while pouring, and make sure that no hardened residue makes its way back into the bottle.

II. Substitution techniques

Use less harsh solvents than IPA

If you are sticking with traditional resins, you can still try to use less harsh solvents than IPA.

There are plenty of alternatives to IPA, many of which work better (and possibly cost less, depending on where you live.)

Unfortunately we couldn’t find a good comparison of the VOC content these emit. (If any of you know more about the subject, please email us!

Why “bio” and “eco” resins are not effective

Some bio resins (such as those made by Anycubic or ELEGOO) claim to be VOC-free.

In our opinion, this is an irresponsible and possibly dangerous label to use, and may give users a false sense of security.

VOC-free in this context likely means that the resin’s VOC emission is lower than a certain regulation threshold in its liquid.

We found two tests measuring the VOC emissions coming from these resins, and they were almost as high as that of regular resin. [Example1][Example2]

III. Engineering control techniques

Keep your windows open

This might sound obvious, but it is important.

Keeping your area ventilated through open doors and windows is one of the cheapest and most effective improvements you can make to air quality.

Air conditioners generally recycle air, so they will not be as effective.

Why an enclosure is not a good solution

Using an enclosure is something we read over and over again in forums.

Unfortunately this solution is not backed up by research.

While an enclosure can be good at trapping fumes, those fumes just stay there, accumulating.

Upon opening the enclosure, the user is hit with a very high concentration of VOCs, which can pose an even more serious health hazard.

Combining the enclosure with a ventilation system or air purifier can make it a much more effective solution.

Install ventilation through a direct exhaust or fume hood

Some users equip their resin printer (either directly or through an enclosure) with an extractor fan.

Most of the polluted air is siphoned outside, preventing it from entering your home or work environment in the first place.

This method is thought to be the most effective way to combat both VOCs and particulate matter, though we haven't found any research testing its efficacy.

It is not as difficult as you might think to implement, but you will need to be at least somewhat technical to do it, as there is no off-the shelf solution.

It may also require some semi-permanent modification to your building, so check with your landlord/ colleagues /significant other before you start.

If you would like to install a ventilation system for your 3D printer, we recommend these guides. They are comprehensive, and easy to follow:

• Ventilation Upgrades for 3D Resin Printing | Asian Joy Co (text)
• 3D Printer Ventilation System - Fumes Eliminated! | Trash Dragon Hobbies (video)

Use a carbon air filter

A slightly less effective option, but one that is much easier to implement is a carbon air filter.

A carbon filter was the most effective preventative solution tested by Yang et al, resulting in a 72% reduction in VOCs during printing, and a whopping 100% reduction while the printer was in standby mode.

The filters must be changed every 2-3 months to stay effective. Before buying a 3D printer with a filter, make sure that the provider offers replacement filters, as this is not always the case.

Other types of filter, (such as HEPA) are not suitable, as they are not effective against VOCs.

VOC measurements are cut down by 50-70% with a carbon filter in use

Resin printers with a carbon filter

This bring us to the advertisement portion of this article.

Our flagship product, the UniFormation GKTwo includes a carbon air filter, and ships with one year’s worth of replacement filters.

It also includes an internal heater, one of the best resolutions on the market, and click-fit parts that make the printing experience much easier.

At YT3DP, we believe it is our responsibility to provide the safest equipment possible, and it should not be down to our customers to fix safety concerns.

Air purifiers with a carbon filter

If you already have a resin printer, you can try to buy a third-party air purifier.

Mini air purifiers

These are carbon filter add-ons made specifically to fit inside resin printers. The ones made by ELEGOO and Anycubic are perhaps the most popular options. The benefits of these is that they can be used with any resin printer, and they are inexpensive. The drawback is that they need to be charged every 24 hours, and replacement filters are not available for all models, so you need to buy a new air purifier every 2-3 months.

Generic air purifiers

These are the same type you would use in your home to improve air quality. You can either put them inside of the room the printer is in, or into the enclosure, if you’re using one. Just make sure it uses a carbon filter, and you’re good to go.

Use a resin vat cover

If you will be using your 3D printer again shortly after a print has finished, it might not make sense to empty and clean all your vat.

In these cases, you can use a resin vat cover to help contain VOCs, and stop them from leaking into the open air.

Our 3D printer, the UniFormation GKTwo, ships with a durable resin vat cover that fits perfectly on top of the vat.

Use an air quality monitor

Air quality monitors can help provide an added level of security for your work environment. Just make sure the one you install measures VOCs (often listed as TVOC for “total volatile organic compounds”).

Keep in mind that no air quality monitor is one hundred percent accurate.

They can tell you when an area is “definitely not safe”, but you should never trust them to tell you that an area is “safe”.

Always use your own judgment and precaution when dealing with hazardous chemicals.

IV. Administrative controls

On to everyone’s favourite. Staff training!

Make sure everyone is aware of the risks

If others also have access to your work area, educate them about the small risks the resin printer emissions represent.

Correct training should help people be more conscious about avoiding the fumes without fearing them.

Implement safety rules

You can implement an informal rule that everyone must stay out of the printing area unless really necessary.

For everyone that will actually be operating the printer, rules should be made about always wearing the proper PPE.

Stay away from the printer while it’s working

Try to plan prints so that the majority of the process takes place while you are away, eg overnight.

If you have to stay in the same space as the printer, try to keep as much distance as possible.

If you can’t help but check on the print every few minutes (we get it), you could install a monitoring camera to do it remotely.

Use signage

A simple sign that says “printer in operation” should help avoid much unnecessary exposure.

You can also print out our infographic to help everyone remember the correct safety measures and PPE at each stage.

Don’t forget about yourself

As we all know, doctors make the worst patients.

It’s easy to fall into the trap of thinking that we are safe, just because we are aware of the risks.

Being the most knowledgeable should instead make you be the best at following procedure, and setting an example for everyone else around you.

V. Personal Protective Equipment

This list is not exhaustive. It only lists PPE to protect against fumes specifically, not direct contact with the resin.

• Mask / respirator with carbon filter. Helps cut down on the number of VOCs you breathe in, and also reduces the smell. Make sure it uses a carbon filter, as other types are ineffective. Especially important if you notice nose or throat irritation.
• Goggles. Help prevent eye irritation.
• Long sleeve shirts and trousers. Helps prevent skin irritation by limiting your exposure.

Bonus content

Bonus: Other factors that impact fume emissions

DLP printers emit 2-3 times the amount of VOCs as laser-based SLA printers. This is probably true for MSLA (LCD) printers as well, due to the similarity in technologies.

Printing on a larger surface area (ie. using a bigger build plate, or making your build plate very full) also increases the amount of VOCs released.

It is possible that both of these caused by the same reason: more energy is being given to resin molecules. Either through increased temperature or by cross-pixel curing.

One study found that higher resin viscosity is also associated with more VOC emissions. I'd like to see a larger sample size before we can say this more confidently, as other differences in the resins also could have affected the outcome.

References

Thank you for reading.

This article draws heavily on the references below, and could not have been possible without them. Thank you to everyone who is trying to make our printing life easier through research.

If you think something should be added or corrected, please let me know at adam@yesthats3dprinted.com. We try to provide the most accurate information possible, but we do make mistakes sometimes.

Stefaniak, Aleksandr B; et al. (May 2019). "Particle and vapor emissions from vat polymerization desktop-scale 3-dimensional printers". Journal of Occupational and Environmental Hygiene. 16(8): 1–13 – via ResearchGate.

Zhang, Qian; et al. (March 17, 2022). "Emissions and Chemical Exposure Potentials from Stereolithography Vat Polymerization 3D Printing and Post-processing Units". American Chemical Society. 29(2): 184–191 – via ACS Publications.

Väisänen, Antti; et al. (11 Nov 2021). "Organic compound and particle emissions of additive manufacturing with photopolymer resins and chemical outgassing of manufactured resin products". Journal of Toxicology and Environmental Health, Part A. 85(5): 198–216 – via Taylor & Francis Online.

Yang, Yiran; et al. (1 January 2018). "Total volatile organic compound emission evaluation and control for stereolithography additive manufacturing process". Journal of Cleaner Production. 170: 1268–1278 – via Science Direct.

Hendrixson, Stephanie (25 September 2021). "Vat Photopolymerization and VOC Emissions: Study Results and User Guidelines". Additive Manufacturing Media.

Kauppila, Ile (Jan 18, 2022). "3D Printing Fumes & Air Quality – A Practical Guide". All3DP.

Goldschmidt, Benjamin (Sep 17, 2022). "3D Printer Enclosure Ventilation with Air Filter: The Basics". All3DP.

"3D Printing - What are VOCs?". 4D Filtration. June 21, 2021.

"Plant Based Resin: Brands and Toxicity". 4D Filtration. January 20, 2023.

electrosync (7 Jun 2022). "How Bad is Resin 3D Printing for Air Quality?". YouTube.