Resin Waste and Disposal

This lesson is not your local law. Waste rules differ by country, state and town, and by the exact product. What follows is what resin makers and their safety data sheets say, so you know what to ask. Your resin's SDS (section 13) and your local waste authority have the final word.

The one rule every source agrees on

Liquid resin, and anything carrying dissolved resin, must not go into a drain, a sink, a toilet or the ground.

• Formlabs: do not pour liquid or partially cured resin into drains or put it in household waste; it may be classified as hazardous waste in your region.
• Formlabs Grey Resin SDS: do not discharge into public wastewater or surface waters; prevent it reaching drains, sewers and waterways.
• Anycubic Standard Resin V2 SDS: do not allow it to enter surface water or drains; notify authorities if it enters sewers or public waters.
• Anycubic Water-Wash Resin+ SDS: the same wording. This resin is classed as harmful to aquatic life with long lasting effects (H412).

Wear your resin PPE for all waste handling: gloves and eye protection, as in Resin PPE.

Why "is resin hazardous waste?" has no single answer

Look at section 13 of two sheets side by side:

SDS	What section 13 says
Formlabs Grey Resin (US format)	As supplied, not considered a hazardous waste under RCRA (the US federal rule); if altered, contaminated or past shelf life, that may not apply. The waste generator is responsible for characterizing the waste under applicable rules.
Anycubic Standard Resin V2 (EU format)	The material and its container must be disposed of as hazardous waste; waste codes are assigned by the user, preferably with the waste disposal authority. Handle contaminated packaging like the substance itself.

Different products, different legal systems, different answers. Neither sheet tells someone in another country what their local rules are. That is why the first step is always your own SDS and the second is your local authority.

Small amounts of liquid resin

For small amounts, when you have no chemical waste stream, Formlabs describes curing the resin first:

1. Put on new nitrile gloves.
2. Pour a small amount into a labeled, transparent, resin-safe container.
3. Leave it in sunlight for 1 to 10 days Maker spec. Formlabs notes 405 nm light and heat cure most effectively.
4. Once it is fully cured, Formlabs says the resin and container can go in household waste. Prusa disagrees for bottles: it says never to put resin bottles, empty or full, in regular waste. Follow your resin maker and your local rules.

That is Formlabs' guidance for its resins. Check that your own SDS and local rules allow it, and that the resin is cured all the way through (no liquid under a skin). Formlabs says to add uncured resin to a chemical waste stream, in accordance with all applicable regulations, where you have one, and to cure it where you do not.

Paper towels, gloves and wipes

Formlabs says to expose resin-soaked paper towels and similar supplies to sunlight or UV light until the resin cures, then dispose of them with household waste. Towels and gloves wet with IPA are different: Formlabs calls spilled IPA an immediate fire and health hazard and says IPA-soaked towels and gloves go with hazardous waste under local regulations. Keep resin-only towels spread out so light reaches all of the resin, keep them out of reach of children and pets while they cure, and follow your local rules if they differ.

Used IPA and other solvents

Solvent with dissolved resin is the waste most often handled wrong. Formlabs says:

• Never pour solvent containing dissolved resin down drains or put it in household waste.
• Check the solvent supplier's SDS first.
• Research your local hazardous waste rules; this will most likely mean a waste disposal service. For small amounts, ask your local waste service for suggestions.
• Tell the service the solvent contains small amounts of methacrylated monomers and oligomers and trace photoinitiator, and keep your resin's SDS on hand for them.

IPA is also flammable; store waste solvent in a labeled, sealed container away from ignition sources until it goes out (see Washing and Curing).

Water-washable wash water

The water you washed water-washable prints in contains resin. It is never drain-safe: the Anycubic Water-Wash Resin+ SDS says not to let the product enter drains or surface water, and that the material must be disposed of as hazardous waste under its EU classification. Collect it in a labeled container and ask your resin maker and local waste authority how to handle it. Do not assume that because it looks like water, it can be treated as water.

Cured resin, failed prints and containers

• Fully cured parts and scraps: Formlabs says cleaned parts and cured resin can be discarded as household waste and cannot be recycled. Make sure they are washed and cured, not sticky.
• Empty bottles and cartridges: follow SDS section 13 and your local rules. The Anycubic sheet says to handle contaminated packaging the same way as the substance; rules for what counts as "empty" differ by jurisdiction.

Waste at a glance

Waste	Never	Ask about
Small amount of liquid resin	Drain, trash while liquid	Curing it first, per maker; local rules
Resin-soaked towels and wipes	Trash while wet with resin	Curing under UV or sun, per maker
Used IPA or solvent	Drain, household trash	Local hazardous waste service
Water-washable wash water	Drain, sink, toilet, ground	Resin maker and local waste authority
Washed, fully cured parts	Recycling bin (Formlabs: not recyclable)	Household waste, per local rules

Setting up a waste spot in your work area from day one makes all of this easier; see Setting Up a Safe Workspace.