3D printing, an additive manufacturing technology, has made rapid prototyping and small-scale manufacturing easier and more accessible. However, this revolutionary process does not come without hazards.

3D printing refers to various processes used to create or replicate an object by using successive layers of material (usually plastics) to create an object. Objects can be of any shape or geometry are produced from a 3D model or from a design fed into the 3D printer by a computer.

With 3D printing, an object can be made by using the following methods:

• Extruding
• Sintering
• Curing

Extruding involves using continuous filament of a thermoplastic material as the feedstock. Sintering is an additive manufacturing procedure that uses a laser as a power source. Curing uses a liquid resin as the feed material and the object is built layer-by-layer and cured; this process takes place slowly.

Each 3D printer is designed to use certain types of materials. The most common type of desktop 3D printer technology joins thin strands, or filaments, made of ABS (Acrylonitrile Butadiene Styrene) or compostable materials, such as PLA, a biodegradable thermoplastic aliphatic polyester derived from corn starch tapioca. Using a computer-generated image, a 3D printer heats and melts the feed material, placing layers of filament on top of one another to form a precise 3D replica of the image.

The materials being fed into the machine (feedstock) can have inherent hazards and may release vapors and gases that may be more hazardous, for example, after they are heated during the 3D printing process.

• Consult the 3D printer manual to be sure you are using the proper feedstock.
• Review safety data sheets for feedstock materials before using.
• Double check what vapors or gases are generated when heating.

UVM Instrumentation & Facility (IMF) has the capability of 3D printing large objects or prototypes using UV light and a photopolymer curing process. This type of 3D printing uses exposure to UV light to harden polymers during the printing process. These materials often contain hazardous monomers, such as acrylates. Additionally, UV light poses a radiation hazard, that can cause damage to vision and skin.

To reduce the potential for nano particles to aerosolize or be inhaled by users, it is best to purchase 3D printers with an enclosure or have an enclosure made.

Nanoparticles (ultrafine particles less than 1/10,000 of a millimeter) are one of the by-products emitted during the 3D printing process. Recent studies have shown that 3D printing using a low-temperature polylactic acid (PLA) feedstock can release 20 billion particles per minute, while a higher temperature acrylonitrile butadiene styrene (ABS) feedstock can release 200 billion.

Nanoparticles are of concern for the following reasons:

• They are very small,
• They have large surface areas, and
• Can interact with the body’s systems, including the skin, lungs, nerves and the brain.

Exposures to nanoparticles at high concentrations have been associated with adverse health effects, including total and cardio-respiratory mortality, strokes and asthma symptoms. While PLA feedstock is designed to be biocompatible, the thermal decomposition products of ABS feedstock have been shown to have toxic effects on lab rodents.

A 2016 study reviews the hazards of 3D printing and filament choices.

3D printers are best located in a room that has additional ventilation.

Heating of certain thermoplastic filament can generate toxic vapors and vapors with high volatile organic compounds (VOCs). Most 3D printers do not come with an enclosure, exhaust ventilation or any filters. The following should be assessed before purchasing and installing a 3D printer:

• Building/Room where 3D printer will be located
• Placement of the 3D printer in the space itself
• Selection of printing feedstock

Other 3D Printing Hazzards

• Hot surfaces - print head block and UV lamp
• High voltage - UV lamp connector, electric outlet safety certified and ground wire.
• Ultraviolet radiation - UV lamp. Don't look at the lamp; make sure the UV screen is intact.
• Moving parts - printing assembly.

3D printing has expanded to include printing of biological materials, such as cells for engineered-tissue generation or scaffolding for lung tissue. With biological 3D printing, there can be a potential exposure to the aerosols generated in the process. Disinfection of the 3D printer beween prints is also of concern. Consult with Risk Management & Safety if you plan to or are already 3D printing biological materials. Some of this work may require an IBC protocol as well.

A 2023 guidance document called "Safe Use of 3D Printing for Higher Education Institutions" has been released.  We encourage you to read it to learn about and implement best practices and evidence-based recommendations to reduce occupant discomfort and health issues from the complex mixture of airborne and ultrafine particles and volatile organic compounds released while 3D printers operate.

In 2016, NIOSH Research Rounds published a study that discusses health and safety considerations when working around 3D printers. Particle emissions are the focus, especially when multiple printers are runing simultaneously. Another consideration is toxic vapors that can be generated by heating plastics. Safety recommendations include the following:

• Use 3D printers ONLY in properly ventilated areas.
• Task ventilation may be useful for some styles of 3D printers.
• Choose low-emitting printers and feed materials/filament when possible.
• Wear proper personal protective equipment. Have a risk assessment to determine what is required.
• Purchase and use the manufacturer’s supplied controls, such as an interlocked enclosure. (Enclosures appear to be more effective at controlling emissions than just a machine cover.)
• Maintain a safe distance from the printer to minimize the inhalation of emitted particles.
• Turn off the printer if the printer nozzle jams, and allow the printer to ventilate before removing the cover.

Laser printers produce images or text on paper by using heat to melt toner powder, which is composed of carbon, plastic, and metals such as iron. Laser printers emit a large amount of particles and asthma-related chemicals. Several factors influence the hazards, such as toner and paper type.

The latest investigations have found that 3D printers emissions may combine to form new compounds, including a chemical linked to asthma. 3D printers can emit smaller particles than those from laser printers (that use plastic toner). These findings, like those in a preceding study, suggest the need to take precautions to reduce emissions from desktop 3D printers in the home and office.

Some 3D printers, like the Stratysus Dimension, require the use of an alkaline bath (corrosive) to remove the extra material surrounding each 3D printed item. Before installing or using an alkaline bath, make sure you have the following:

• Proper lab ventilation,
• Proper administrative controls, such as a written standard operating procedure,
• Proper chemical safety training, and
• Proper personal protective equipment to handle corrosive lliquids.