ASA stand for Acrylonitrile Styrene Acrylate, is a terpolymer, meaning it’s a type of plastic formed by linking 3 different monomers:
- Acrylonitrile (AN): This component provides chemical resistance, good moisture absorption, and dimensional stability to the final ASA filament.
- Styrene (S): Styrene contributes to the shiny surface finish often seen in ASA prints.
- Acrylate (A): This monomer enhances the material’s overall mechanical strength
The potential toxicity of ASA filament fumes is indeed related to its three primary components—acrylonitrile, styrene, and acrylate. When heated during 3D printing, these components release harmful volatile organic compounds (VOCs) and ultrafine particles (UFPs)
II. Health effects
1. VOCs
The first thing we need to understand is that not all VOCs are dangerous for human health. However, in this case, we are looking at three specific VOCs:
🔴 Styrene: According to NIOSH, exposure to styrene, a component of ASA filament, can lead to significant health effects, including changes in color vision, cognitive impairments, and balance problems. High concentrations may also cause hearing loss, as observed in animal studies.
🔴 Acrylonitrile: The toxicological sheet from the INRS (Institut National de Recherche et de Sécurité) in France publied in November 2017, which provides detailed information on the substance acrylonitrile. Toxic if ingested, inhaled, or absorbed through the skin. It can cause severe eye damage, skin irritation, respiratory irritation, and allergic skin reactions. Acrylonitrile is also a potential carcinogen and is toxic to aquatic life with long-lasting effects.
🔴 Acrylates: The International Agency for Research on Cancer (IARC) and the U.S. Environmental Protection Agency (EPA) classify certain acrylates as possible human carcinogens. This classification indicates a potential link between exposure to acrylates and an increased risk of developing cancer. Long-term exposure to acrylates can lead to toxicity in various organ systems, including the liver, kidneys, and respiratory system. This toxicity may manifest as chronic illnesses and compromised organ function.
All subplots indicate that most compounds have minimal emissions at lower temperatures, with emissions rising sharply as the temperature approaches and exceeds 200°C (this study conducted by Gdańsk University of Technology in Poland)
This necessitates caution and appropriate safety measures when working with ASA filaments at elevated temperatures to mitigate health risks associated with these emissions VOCs.
2. Ultrafine particles (UFPs)
Our test indicates that ASA filaments are the most emissive among the tested filaments (ASA, PETG, PC, PLA), with significantly higher nanoparticle emissions:
- ASA (red line): Shows the highest emission levels with peaks reaching up to nearly 2,000,000 p/cm³. It is the most emissive filament among those tested.
- PC (orange line): Also has significant emissions but lower than ASA. Peaks occur around the same time intervals.
- PETG (blue line) and PLA (green line): Both show much lower emission levels compared to ASA and PC. Their emission profiles are relatively flat and stay below 200,000 p/cm³
Health Risks:
- UFPs are small enough to penetrate deep into the lungs and even enter the bloodstream upon inhalation.
- Exposure to UFPs has been linked to respiratory and cardiovascular health effects, including inflammation, exacerbation of asthma, and increased risk of cardiovascular diseases.
III. Safety measures
3D printing enclosure and air filtration system
🟢 Containment of fumes: An enclosure with air filtration (HEPA fitter and carbon active) helps contain these fumes, preventing them from dispersing into the surrounding environment and reducing exposure to users.
🟢 Improved ventilation control: Enclosures can be equipped with ventilation systems that direct fumes and particles outside or through filters. This improves control over indoor air quality by effectively managing emissions from the printing process.
🟢 Reduction of ultrafine particles: Ultrafine particles (UFPs) are small enough to penetrate deep into the lungs and bloodstream, posing respiratory and cardiovascular health risks. Proper filtration systems with HEPA fitter and carbon active can capture 99.95% UFPs and VOCs, mitigating their potential harm to users.
🟢 Higher-quality prints: When we print with ASA filament, the bed should be heated to at least 100 °C, so using an enclosure for 3D printing with ASA helps maintain optimal printing conditions, including consistent temperature control and reduced environmental variables
Other recommendations:
🟢 Open room with airflow: If an enclosed printer isn’t available, print in a well-ventilated room with open windows and, if possible, a fan directing fumes away from you.
🟢 3D printer farm: If using multiple printers simultaneously, ensure proper ventilation for the entire printing area.
A perfect electrical box printed in ASA filament thanks to our enclosure
Note: During the winter, ideally with a fan or other exhaust system directing fumes away from you.
Toxic emission risks associated with 3D printing | Rapport 2024
IV. Conclusion
While ASA filament offers desirable mechanical properties and weather resistance, it also poses potential health risks through the emission of volatile organic compounds (VOCs) and ultrafine particles. These emissions have been associated with respiratory irritation, neurological effects, and long-term health concerns such as carcinogenicity.
To mitigate these risks, it is essential to prioritize safety measures such as adequate ventilation, the use of 3D printing enclosures with effective filtration systems, and the implementation of personal protective equipment. By adhering to these precautions, users can minimize exposure to ASA filament fumes and create a safer working environment, ensuring both the quality of prints and the well-being of individuals involved in the 3D printing process.
References
- Wojnowski W, Marć M, Kalinowska K, Kosmela P, Zabiegała B. Emission Profiles of Volatiles during 3D Printing with ABS, ASA, Nylon, and PETG Polymer Filaments. Molecules. 2022 Jun 14;27(12):3814. doi: 10.3390/molecules27123814. PMID: 35744939; PMCID: PMC9229569.
- https://www.cdc.gov/niosh/topics/styrene/
- https://www.inrs.fr/dms/ficheTox/FicheFicheTox/FICHETOX_105-3/FicheTox_105.pdf
