Is UV Resin Toxic After Curing?

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Many experts agree that UV resin is no longer toxic after curing, but some still argue that it remains toxic after curing. So our team set out to confirm the truth about the toxicity of UV resin after curing. We have compiled the result of our findings in this post.

Is UV resin toxic after curing? Resins become non-toxic when it cures fully. Resins cure fully when it becomes completely hardened, solid, and thoroughly washed. And as a result of this, it becomes an inert substance and no toxic leach can exude from it. Uncured UV resins are toxic because of their chemical properties. But when you cure resins, the chemical properties change. In this final stage, when the resin is fully cured, it is safe to touch it and place your items on it.

Before it fully cures, the resin is liquid-based and is very toxic, so you must take proper precautions to ensure your safety. However, there are still a few safety precautions you need to take even after curing resins. As you read on, we will explain these and a few other facts about the toxicity of cured vs. uncured resins.

Is UV Resin Toxic After Curing
Image by kalhh from Pixabay

Is Cured UV Resin Toxic?

Cured resin is not toxic because its photo-polymerization is complete already and the plastic becomes inert. Firstly, this means that the resin material hardens and solidifies completely, so no toxic chemicals can leak from it anymore. This makes it safe for the skin. Secondly, since every molecule in the resin has reacted with nothing left behind, no more fumes or VOCs (volatile organic compounds) can come off it and cause air pollution or irritation. This makes cured resins safe for the eyes and lungs. Unlike uncured resins, cured resins will not cause any respiratory distress.

This means that cured resin can safely come in contact with your skin. But then, some manufacturers add substances, like extenders, to their 3D parts and these could be toxic. But uncured resin, without any toxic additive, is not toxic. That’s why experts advise curing resins before disposing of them. That way, you are sure that you’re not polluting the environment and ecosystem with a toxic substance.

Is Cured Resin Hazardous?

Some experts have claimed that cured resins could still be hazardous. This means that although it will not cause death when living organisms come in contact with, absorb, or ingest it. But then, they can still cause some hazards, such as allergic reactions, for those who have allergies.

Is Cured Resin Safe for Your Skin?

There is nothing to worry about if you have no allergies. You can use jewelry made with resins without any issues so long as it’s fully cured. There are many fashionable wearables, including jewelry and rings, made with resins. These wearables can be in constant touch with your skin with no issues so long as you have no allergies and it’s fully cured. But if the resin part is not fully cured or you have allergies, there may be skin irritation.

Can You Eat From Cured Resin?

Not all resins are approved for direct food contact by the FDA. But for the most part, fully cured resins should be safe to eat from if there is no other toxic or hazardous additive. This notwithstanding, you should not eat from any resin plate or material if it is not approved for direct food contact by the FDA.

The FDA has thorough regulations that manufacturers must comply with before food contact approval can be given. In the end, you must realize that not all resin parts are made for food contact. So you must look for specific brands that are compliant with the standards of the FDA for food contact.

Can Cured Resin Become Toxic Again?

Cured resin cannot become toxic again. But if it breaks down, it can release toxic leaches into the environment. Experts say that resin can over-cure due to extended exposure to UV light, which would break down the plastic. This, in itself, is not toxic but it can cause the plastic to melt or become brittle and release toxic substances into the environment. As such, you should try, as much as possible, to keep your resin 3D parts away from intense, direct sunlight for an extended time.

The major concern with the toxic effects of resin breakdown is not about the resin materials in use. It’s with those that have been disposed of. You should always dispose of resin material in the designated area for organic waste by your local authorities. You can also allow a waste management service to help you handle it.

✅ Video – 3D Printing: Safe Way of Disposing Resin

If you’re confused about how to dispose of your excess resin after printing, you should watch this video. To start with, you will learn more about hazardous wastes in general and the dangerous effects they could have. That way, you will understand why it’s important to dispose of every organic waste, including resins, properly. And then, you will see the possible solutions to the problem of resin disposal.

How Toxic is Uncured Resin?

Some of the toxic effects of uncured resins include skin irritation, lung irritation, and environmental pollution, among others. These toxic effects are serious enough for you to pay thorough attention to all necessary safety precautions while using it for anything. As toxic as uncured UV resin is, it won’t harm or hurt you if you pay attention to the safety precautions.

What’s more, beyond just the resin material, you must also pay attention to every material you used to store or clean it. You should apply safety precautions around these materials while handling and disposing of them too.

Here are some of the major toxic effects of resin:

Skin Irritation

Your bare skin should never come in direct contact with liquid UV resin. This can cause serious irritation and inflammation. Your skin can become red, swollen, and painful or you might experience severe itching and develop a rash.

What’s more, the problem with resin exposure is that the more your skin is exposed to resins, the more severe the irritation becomes. In other words, skin irritations from resins worsen progressively. As such, you should always wear gloves whenever you are using uncured resins.

Respiratory Distress

Resins naturally release fumes into the atmosphere when it is uncured. These fumes contain volatile organic compounds, which can irritate your lungs and cause respiratory distress. As such, whenever you are using resins, make sure the area has a good ventilation system. You can also wear a respiratory mask to protect yourself.

✅ Video – Resin Safety Precautions

Do you know the 5 basic ways to keep safe while using resin? In this video, Sarah Types shares 5 simple safety tips you must apply whenever you’re handing resin. She is an expert in resin printing and this is one of her many resin tutorials. Some of the points she covers include ventilation, skin protection, and eye protection.

Not for Internal Use

You should never expose uncured resins to your eyes or ingest them. You should not eat from any resin material that’s not FDA approved and fully cured. The fumes from resins can also irritate your eyes, so you should protect your eyes with goggles whenever you’re working with uncured UV resins. Standard resins can cause permanent damage to your eyes and internal organs: and very quickly too.

Not Environmentally Friendly

Uncured resin is toxic to our environment and ecosystem. It is especially toxic to aquatic life, as its molecules can negatively affect the neurological functions of aquatic animals, including fishes, and kill them. Up until now, scientists are still trying to fully understand the full extent of the harmful effects of uncured resins on the environment.

Related Questions

Why Is My UV Resin Sticky After Curing?

UV resins often remain tacky or sticky if you only cure them for a short while, say a few minutes. What happens in those cases is that the resin has hardened on the outside but it’s still soft inside. Sometimes too, if you overheat the resin while curing, the surface may harden very quickly while the inside is still soft.

To avoid stickiness after curing, you should cure your resins slowly, using weak light. This will significantly reduce stickiness. Then, after curing, wipe the resin part quickly with a cloth moistened with isopropyl alcohol. This will remove any residual tack and leave you with a smooth, fully-cured resin part.

How Long Does UV Resin Need To Cure?

You can full-cure a small to average-sized resins part in 15 to 30 minutes. Sometimes, it could even take less than that of the resin part is very small. Engineering resins take longer to cure than standard resins; they could take 60 minutes to cure completely. What’s more, the duration for post-curing, also varies slightly for white, black, grey, and black resins. Black resins take the longest time to cure because black color absorbs the least UV light ray.

In summary, the type of resin you are using, as well as the size and color of your resin part affects the duration of curing. But no matter how long it takes, it’s important to wait patiently for curing to be complete. It helps your resin part to attain its optimum rigidity, strength, heat-resistance, structural integrity, strength, and durability.

Will UV Resin Cure On A Cloudy Day?

A cloudy day will not affect resin curing if you are using a UV machine to cure your resin part. But if you intend to cure your resin part with sunlight, you should not do so on a cloudy day. On a cloudy day, sunlight will not emit adequate UV ray that’s enough to cure resin parts.


Cured resin is not toxic but it could be hazardous if you don’t dispose of it properly. While handling uncured resin, you should pay attention to safety precautions. And for cured resin, while they are safe to handle, you should not eat from a resin material except it is FDA-approved for food contact. And for the sake of our ecosystem, make sure you always cure your left-over resins and dispose of them at the place designated by your local authorities.

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