The NIOSH is a part of America’s CDC (Centers for Disease Control). The NIOSH itself is The National Institute for Occupational Safety and Health for the United States. It is the part of the government tasked with researching into the safety of workers in many professions. At 3DPrint.com we noticed a number of very interesting articles come out by NIOSH researchers about 3D printing. We were especially impressed with their thoughtful and thorough research on carbon nanotubes in 3D printer filaments. There is also a very informative post about 3D printers and safety on the NIOSH website. We’ve always been worried about 3D printing safety including fine particles and especially fumes from 3D printers. At 3DPrint.com we think that we are potentially creating significant health issues with some 3D printing practices. We, therefore, reached out to the NIOSH for some guidance. A group of NIOSH researchers took the time to respond to us with some best practices for 3D printer safety. We’re very thankful for their well thought out and clear answers to our questions. We must, as they have, qualify their statements as an initial response but we do believe that this is the clearest and most extensive look into 3D printing safety online.
“It is important to note that there is a current lack of data on 3D printer emissions. In addition, the rapidly shifting description of the “workplace/production environment,” the availability of this technology beyond industrial applications, and the tremendous variety of feedstock polymers that are commercially available or can be made by consumers mean that additional research is needed to evaluate these emissions’ possible health effects.”
1) If I 3D print with FDM at home should I get a fume hood or HEPA/Carbon filtration just in case?
‘NIOSH focuses on worker health and our research is performed in the laboratory and in occupational settings, which can be quite different from homes. Consideration of whether to use a fume hood or filtration will depend on several factors, including the design of the 3-D printer, the type of filament being extruded (filaments are materials (plastic, nylon or other) that are fed into the printer in order to create the final object), the size and air movement in the room in which it is being used, and who is occupying the room (children, adults, people with pre-existing health problems).
While there are no occupational exposure limits for the small particles emitted by 3-D printers, there are some exposure limits for specific chemical vapors that are emitted during printing. For occupational settings, these chemical exposure limits can be used to guide the selection of appropriate controls to reduce exposures to a safe level. In workplaces, NIOSH research has shown that appropriately designed and operated local exhaust ventilation with HEPA/carbon filtration reduces the amounts of particles and chemicals in air. It is important to understand that occupational exposure limits are intended to protect adults in workplace settings and, at this time, we do not know what levels of particles or chemical vapors would be safe for children and others in homes. Given this uncertainty, it is difficult to recommend specific levels that should be achieved when trying to reduce emissions in homes, though use of a printer in a well-ventilated area could help lower emissions.”
2) What are the risks of 3D printing?
“For FDM 3-D printers, there are risks related to the printer itself and potentially from the emissions. Risks related to the printer are similar to those associated with working with other types of machines and may include electrical shock from damaged power cords, burns from touching hot surfaces such as the extruder nozzle, and injury such as cuts from contact with sharp edges or contusions from contact with moving parts. At this time, our understanding of risks from particle and chemical vapor emissions from 3-D printers is limited.
In one study done by NIOSH, rats exposed for 1 hour to particle and vapor emissions from a FDM 3-D printer using ABS filament (a type of plastic material) developed acute hypertension, indicating the potential for cardiovascular effects. In another NIOSH research study, lung cells exposed to FDM 3-D printer emissions from printing with ABS and polycarbonate for about 3 hours showed signs of cell damage, cell death, and release of chemicals associated with inflammation, suggesting potential for adverse effects to the lungs if emissions are inhaled. These in vitro findings need to be confirmed with more extensive in vivo studies. It is important to understand that exposures used in toxicology studies may not be the same as those encountered by workers or in homes for a number of reasons, including the use of ventilation in workplaces or the amount of fresh air brought into homes by the heating and cooling system.”
3) How would I best protect myself against 3d printing risks?
“Risks related to the printer itself can often be eliminated by safe work practices and the design of the 3-D printer. For example, as with any electrical device used at work or in the home, daily inspection of the electrical cord can help to identify if the cord is damaged and should not be used. After an object is printed, allowing sufficient time for the extruder nozzle to cool down before removing the object from the build chamber will reduce the risk of burns. NIOSH researchers often observe smaller 3-D printers being used in workplaces that are also purchased by consumers for private use. Using a 3-D printer with a cover or doors that prevent the user from reaching in while machine parts are moving will help reduce the risk of injury.
- At this time we do not know what levels of exposure causes adverse health effects, so we can’t recommend safe levels of exposure to 3-D printer emissions whether in the workplace or in homes. In occupational settings, we use the “hierarchy of controls” to protect workers from risks on their jobs. The hierarchy of controls specifies, from most preferred to least preferred, the types of controls that should be used to reduce occupational exposures:
- The most preferred method is to substitute or eliminate the hazard. For example, in the case of FDM 3-D printing with filaments that contain carbon nanotubes, the emission of plastic-particles that contain carbon nanotubes can be eliminated by not using that type of filament if it is not necessary for the performance of the built object.
- If a risk cannot be eliminated, engineering controls such as a fume hood or local exhaust ventilation (a system that specifically ventilates the printer rather than the air in a room) with HEPA/carbon filtration would be the next preferred method to reduce emission levels. Some 3-D printers are now being sold with built-in filtration units.
Alternatively, a printer owner may purchase an after-market fan/filter systems to reduce emissions. However, NIOSH researchers have not yet evaluated how well these built-in or after-market filtration systems work. It is important to understand that for engineering controls such as fume hoods or local exhaust ventilation with filtration to be effective, these systems must be properly designed, built and operated.
In one workplace, NIOSH researchers showed that an appropriately designed and operated local exhaust ventilation with HEPA/carbon filtration reduced the amounts of particles and chemicals in air. NIOSH researchers have also observed that in some workplaces where the ventilation system is not built correctly that the chemicals are released back into the room air. Additionally, systems that use carbon filters to remove organic chemical vapors need to be monitored over time because the charcoal has a finite capacity to adsorb chemicals. Once this capacity is reached, the charcoal filter needs to be replaced or it will not capture additional organic vapor emissions.
- If engineering controls cannot reduce the risk to an acceptable level, administrative controls may be used. An example of an administrative control is that NIOSH researchers have observed in some workplaces that employees do not enter the room where 3-D printers are operating unless it is necessary (e.g., to perform maintenance or to retrieve a built object).
Finally, if none of these controls can reduce emissions to an acceptable level, the least preferred control is the use of personal protective technologies such as respirators or dust masks. In workplaces, respirators are the least preferred means of control because they do not remove the exposure, they only reduce the amount that might be inhaled; this depends on the proper selection of filters and cartridges that remove contaminants while breathing. Additionally, to be effective, respirators rely on the worker to properly wear and use the mask. To wear a respirator, a user must be medically cleared by a physician and it must be properly fitted and retested each year to ensure fit. The user must be properly trained on how to wear, remove, and maintain the respirator. NIOSH researchers have observed in some workplaces where 3-D printers are used that some employees with facial hair will put on a respirator, but the hair prevents the respirator from forming a tight seal with their face so the mask does not provide any protection to the worker.”
4) If I had a 3D printer at a school what should my safety precautions be?
“NIOSH focuses on worker health and our research is performed in the laboratory and in occupational settings, which can be quite different from environments such as homes or schools. For example, 3-D printers may be used with different frequency in schools and there may be only one printer operating in a large classroom as opposed to many printers in a small workspace. These differences will influence the types of controls implemented to reduce emissions.
There are no occupational exposure limits for the small particles emitted by 3-D printers but there are some exposure limits for specific chemical vapors that are emitted during printing. For occupational settings, these chemical exposure limits can be used to guide the selection of appropriate controls to reduce exposures to a safe level.
It is important to understand that occupational exposure limits are intended to protect adults in workplace settings. At this time, we do not know what levels of particles or chemical vapors would be safe for children in schools. Given this uncertainty, it is difficult to recommend specific levels that should be achieved when trying to reduce emissions in schools. In workplaces, NIOSH research has shown that appropriately designed and operated local exhaust ventilation with HEPA/carbon filtration reduces the amounts of particles and chemicals in air. If exhaust ventilation is not feasible, use of a printer in a well-ventilated area could help lower emissions.”
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