Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries and Small Businesses

Approaches to Safe 3D Printing:

A Guide for Makerspace Users, Schools,

Libraries, and Small Businesses

Centers for Disease Control

and Prevention

National Institute for Occupational

Safety and Health

Front and back covers:

Photo by ©AzmanJaka/iStock/Getty Images Plus

Approaches to Safe 3D Printing:

A Guide for Makerspace Users, Schools,

Libraries, and Small Businesses

DEPARTMENT OF HEALTH AND HUMAN SERVICES

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

ii | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

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Suggested Citation

NIOSH [2023]. Approaches to safe 3D printing: a guide for makerspace users, schools, libraries,

and small businesses. By Hodson L, Dunn KL, Dunn KH, Glassford E, Hammond D, Roth G.

Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control

and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Pub-

lication 2024-103, https://doi.org/10.26616/NIOSHPUB2024103.

DHHS (NIOSH) Publication No. 2024-103

DOI: https://doi.org/10.26616/NIOSHPUB2024103

November 2023

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | iii

Foreword

Use of three-dimensional (3D) printing technology is becoming a prominent part of our mod-

ern world. However, some 3D printer users have expressed concerns about potential exposures to

ultrane particles, chemicals, and safety hazards. ese printers are often used in non-industrial

workplace settings such as makerspaces, schools, libraries, and small businesses.

Based on these concerns, NIOSH began evaluating emissions from dierent printer and lament

combinations operating in both chamber studies and workplace environments to understand

the potential health and safety risks. is report summarizes NIOSH’s ndings and recommen-

dations for controls to protect workers using 3D printers in makerspaces, schools, libraries, and

small businesses.

John Howard, MD

Director, National Institute for Occupational

Safety and Health

Centers for Disease Control and Prevention

is page intentionally blank.

Contents

Foreword................................................................. iii

Abbreviations ............................................................. vii

Acknowledgments ......................................................... ix

1 Introduction ....................................................... 1

2 Types of 3D Printing in Non-industrial Workplaces ......................... 2

2.1 Fused lament fabrication ............................................. 2

2.2 Vat photopolymerization ............................................... 4

3 Potential Health and Safety Risks from the Use of 3D Printers................ 5

3.1 Pre-printing ......................................................... 5

3.2 Printing ............................................................ 5

3.3 Post-printing ........................................................ 5

3.4 Maintenance and cleaning.............................................. 6

3.5 Emissions ........................................................... 6

3.6 Solvents ............................................................ 7

3.7 Heat ............................................................... 7

3.8 Mechanical risks/moving parts........................................... 8

3.9 Lasers.............................................................. 8

3.10 Electrical .......................................................... 8

3.11 Noise ............................................................. 8

3.12 Robotics and automated systems........................................ 9

3.13 Take-home exposures................................................. 9

4 Risk Management Considerations ...................................... 9

4.1 Risk management plan ................................................ 9

4.2 Hierarchy of controls .................................................. 10

4.3 Elimination/substitution................................................ 11

4.4 Engineering controls .................................................. 11

4.5 Administrative controls ................................................ 18

4.6 Personal protective equipment........................................... 19

vi | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

5 Exposure Assessment................................................ 20

6 Additional Information .............................................. 21

7 Conclusions ....................................................... 21

References ............................................................... 22

Appendix A: Workplace Poster ................................................ 27

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | vii

Abbreviations

3D three-dimensional

ABS acrylonitrile butadiene styrene

ACH air changes per hour

ACGIH

American Conference of Governmental Industrial Hygienists

ANSI American National Standards Institute

ASSE American Society of Safety Engineers

CAD computer-aided design

CFR Code of Federal Regulations

CLEAPSS Consortium of Local Education Authorities for the

Provision of Science Services

CLIP continuous liquid interface production

dB(A) decibels, A-weighted

DLP digital light processing

DPP daylight polymer printing

FDA Food and Drug Administration

FFF fused lament fabrication

HEPA high eciency particulate air

HIPS high-impact polystyrene

HSE Health and Safety Executive

IARC International Agency for Research on Cancer

ILO International Labour Organization

ISO International Organization for Standardization

laser light amplication by stimulated emission of radiation

LEV local exhaust ventilation

LIA Laser Institute of America

NIH National Institutes of Health

NRTL Nationally Recognised Testing Laboratories

OSHA Occupational Safety and Health Administration

PAH polycyclic aromatic hydrocarbon

PC polycarbonate

PEL permissible exposure limit

PET polyethylene terephthalate

PETG polyethylene terephthalate glycol-modied

viii | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

PLA polylactic acid

PPE personal protective equipment

PVA polyvinyl alcohol

REL recommended exposure limit

SDS safety data sheet

SLA stereolithography

TWA time -weighted average

UK United Kingdom

UV ultraviolet

VOC volatile organic compound

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | ix

Acknowledgments

e authors appreciate the contributions of the following NIOSH personnel who provided

guidance, feedback, and review of the document, including Elizabeth Arnold, BS; Jacob Bartels,

MS; Lauren Bowers, BS; Charles Geraci, PhD (retired); Mark Methner, PhD; Susan Moore,

PhD; Yong Qian, PhD; Aleksandr Stefaniak, PhD; and Jay Vietas, PhD.

Special appreciation is expressed to the following individuals for serving as external reviewers and

providing comments that contributed to the development of this document:



Dave Abrams, MSPH

ARS Environmental Health, Inc.



John Baker, MS, MBA

BSI EHS Services and Solutions



Jean Bossart, M. Eng.

Marston Science Library, University of Florida



Janet Carter, PhD

OSHA



Joanna Matherson, PhD

Consumer Product Safety Commission



Keith Rickabaugh, BS, MBA

RJ Lee Corp.



Sayon Robinson, PhD

Consumer Product Safety Commission



Jim Sillhart, MES

University of Pennsylvania

is page intentionally blank.

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | 1

1 Introduction

ree-dimensional (3D) printing technology is becoming a prominent part of modern inno-

vation due to its usefulness in accelerating product development and prototyping, as well as in

producing complex and precision parts [Campbell et al. 2011; Campbell et al. 2012]. Parts built

by 3D printing (sometimes referred to as additive manufacturing) are built layer by layer and are

highly customizable. It can take weeks or months to build and receive a part using traditional

manufacturing (e.g., machining, molding) processes. However, 3D printing can turn computer-

aided design (CAD) models into physical parts within a few hours, producing one-o concept

models, functional prototypes, and even small production runs for testing. 3D printing allows

designers and engineers to bring ideas to fruition faster, and it helps companies bring products

more quickly to the market. In addition to industrial applications, 3D printers are now available

for use in diverse non-industrial places such as makerspaces, schools (including colleges and

universities), libraries, and small businesses. A makerspace is a place where people with shared

interests, especially in computing or technology, can gather to work on projects while sharing

ideas, equipment, and knowledge.

Concerns have been raised about potential exposure to ultrane particles (having a primary

particle size less than 100 nanometers) and chemicals in addition to possible safety hazards from

using 3D printers [Bharti and Singh 2017; Chan et al. 2018; CLEAPSS 2020; Mooreeld-Lang

2014; Roney et al. 2016; Sesto 2017]. Despite the rapid growth in availability and use of 3D

printers, little scientic literature has focused on the potential implications of exposure to emis-

sions from 3D printing equipment. Substances associated with similar types of plastics and res-

ins that are used in 3D printers have been identied as causative agents of occupational diseases

in the manufacturing sector. For example, volatile organic compounds (VOCs) and polycyclic

aromatic hydrocarbons (PAHs), along with metal dust emissions and ultrane particles, can

cause disease, and all have been detected in 3D printer emissions [Stefaniak et al. 2017a, 2017b,

2019a,b,c; Steinle 2016; Stephens et al. 2013]. Because 3D printing is an emerging industry

with a relatively short history, it is dicult to know the potential occupational health outcomes

stemming from exposure to these emissions.

To understand the potential health and safety risks, NIOSH has evaluated emissions from

dierent printer and feedstock combinations operating in chamber studies and workplace

environments. NIOSH then used this knowledge to create risk management recommendations

to protect workers. is document summarizes the ndings and suggests options for controls

to protect workers and users from exposures to ultrane particles, chemicals, and safety hazards

while using 3D printers in makerspaces, schools, libraries, and small businesses.

2 | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

2 Types of 3D Printing in

Non-industrial Workplaces

ere are several types of 3D printing processes, but fused lament fabrication and vat photopo-

lymerization are the types most likely to be found in makerspaces, schools, libraries, and small

businesses due to lower purchase and material costs [Bharti and Singh 2017].

2.1 Fused lament fabrication

Fused lament fabrication (FFF) is the most common type of 3D printing process and is used

by most desktop 3D printers (Figure 1). FFF printers are the most popular for libraries simply

because they are inexpensive, take up minimal space, and are easy to set up and use [Bharti and

Singh 2017; Mooreeld-Lang 2014].

Figure 1. FFF desktop 3D printers.

Photo by MakerBot

Feedstock material in the form of a lament is fed into the extruder of the printer head (Figure 2),

where the lament is heated to a temperature high enough to soften or melt it. is softened

lament then extrudes from the computer-controlled nozzle to create an object one layer at a time.

e print platform lowers, or the print head raises, to add subsequent layers and eventually to

complete the printed part.

Some FFF printers use a support material in addition to the modeling material. e modeling

material is what constitutes the nal product, while the support acts as scaolding that can be

removed (broken o or dissolved) after printing is complete.

Desktop FFF 3D printers use a wide variety of lament materials including, but not limited to,

the following:



Polylactic acid (PLA)



Acrylonitrile butadiene styrene (ABS)



Nylon



Polyethylene terephthalate (PET) or polyethylene terephthalate glycol-modied (PETG)



Polyvinyl alcohol (PVA)



Polycarbonate (PC)



High-impact polystyrene (HIPS)



Other polymers including those containing ceramic materials

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | 3

Feedstock material in the form of a lament is fed into the extruder of the printer head (Figure 2),

where the lament is heated to a temperature high enough to soften or melt it. is softened

lament then extrudes from the computer-controlled nozzle to create an object one layer at a time.

e print platform lowers, or the print head raises, to add subsequent layers and eventually to

complete the printed part.

Some FFF printers use a support material in addition to the modeling material. e modeling

material is what constitutes the nal product, while the support acts as scaolding that can be

removed (broken o or dissolved) after printing is complete.

Desktop FFF 3D printers use a wide variety of lament materials including, but not limited to,

the following:



Polylactic acid (PLA)



Acrylonitrile butadiene styrene (ABS)



Nylon



Polyethylene terephthalate (PET) or polyethylene terephthalate glycol-modied (PETG)



Polyvinyl alcohol (PVA)



Polycarbonate (PC)



High-impact polystyrene (HIPS)



Other polymers including those containing ceramic materials

e most commonly used types of 3D printer media are PLA, ABS, and nylon. PLA is a type of

biodegradable plastic made from a variety of natural substances that include sugar, corn starch, or

sugar cane. Many features make PLA desirable for 3D printing. It is the lament of choice for most

extrusion-based 3D printers because it can be printed at a low temperature (typically 190–220°C,

or 374–428°F), and it does not require a heated bed [Tyson 2018]. ABS is a plastic made from

petroleum-based substances. ABS is quite strong and is often used to create toys such as Lego

building blocks [Homan 2018]. Nylon is a synthetic polymer created from a chemical class of

substances known as polyamides. Nylon is resilient, strong, and durable, yet exible. It melts at a

higher temperature (about 240°C , or 464°F) than ABS and PLA laments [Homan 2018].

Figure 2. Schematic of a fused filament print head.

Illustration by NIOSH

4 | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

PET is rarely used as a 3D printing lament, but its variant PETG is becoming increasingly

popular. e “G” stands for “glycol-modied,” and the resulting lament is clearer, less brit-

tle, and most importantly, more amenable for printing than its base form (i.e., PET). For this

reason, PETG is often considered an excellent middle ground lament between PLA and ABS,

since it is more exible and durable than PLA and easier to print with than ABS [All3DP 2022].

Once the 3D object is formed, it may undergo post-processing such as removal of support materials

chemically, or manually smoothing edges by sanding, or painting.

2.2 Vat photopolymerization

Vat photopolymerization technology uses a vat of liquid photopolymer resin that is cured by an

ultraviolet (UV) or laser light source focused onto a build platform (Figure 3). e light source

causes a reaction with photoinitiators in the resin that induce cross-linking of resin polymers,

which results in solidication. By repeatedly exposing layers of resin to ultraviolet light, an object is

built layer by layer. is 3D printing process is popular for its ne details and exactness.

Once completed, the 3D object is removed from the printer and detached from the supporting

platform. e 3D object usually undergoes post-processing, which typically involves placing the

3D object in a chemical bath (often isopropanol) to remove any excess resin and then post-curing

in a UV oven. ese actions render the nished item stronger and more stable. Depending on

the object, it may then go through a hand-sanding process and subsequent painting. Photopoly-

mers are thermosets, meaning that the material strengthens as it is heated, and once cured by

a UV light, it cannot be remelted. Vat photopolymerization 3D printing technologies include,

but are not limited to, the following: stereolithography (SLA), digital light processing (DLP),

continuous liquid interface production (CLIP), and daylight polymer printing (DPP).

Figure 3. Vat photopolymerization, SLA printer using a “bottom-up” approach to build a part. Image

source: Proform Rapid Prototyping, 2018. “Stereolithography 3D Printing” (https://www.proform.ch/

en/technologies/3d-printing/stereolithography).

Illustration by PROFORM AG

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | 5

3 Potential Health and Safety Risks

from the Use of 3D Printers

Potential health and safety hazards vary widely depending on the technology and materials used,

as well as where the printers are located and any controls that may be in place.

3.1 Pre-printing

Depending on the type of 3D printing, some pre-printing activities can have potential health

and safety risks. Some activities with higher potential for inhalation and skin exposures during

pre-printing include cleaning the printer heads and nozzles [NIOSH 2020a]. is hazard is due

to the associated solvents and other cleaners used during this step and the potential exposure to

those chemicals. Some chemicals in liquid resins used for vat photopolymerization 3D printing

may cause skin irritation or sensitization [Bowers 2022]. Inadvertent contact with the nozzle of

an FFF 3D printer during pre-printing heating can cause skin burns. Activities with lower po-

tential for inhalation and skin exposures include loading solid laments into printers, changing

printer heads/nozzles, and prepping the build plate [NIOSH 2020a].

3.2 Printing

Potential exposures can occur during the 3D printing process. Activities with higher potential

for exposures during the print process include using printers in a small workspace or general

oce area, working near the printer, and attending to a printer quickly after print failures and

during printer start up [Azimi et al. 2016; Kim et al. 2015; NIOSH 2020a; Stefaniak et al.

2017b; Steinle 2016; Stephens et al. 2013; Yi et al. 2016].

Activities with lower potential for exposure include printing in an enclosed chamber equipped

with a ltering device, or exhausted to the outdoors, and using video camera monitoring to

avoid standing too close to the printer [Azimi et al. 2016; Kim et al. 2015; NIOSH 2020a;

Stefaniak et al. 2017b; Steinle 2016; Stephens et al. 2013; Yi et al. 2016].

3.3 Post-printing

Post-printing work activities can also result in variable potential for exposure. Some examples of

activities with higher potential for exposure include opening printer doors, removing support

structures using solvents or other chemicals, or post-processing activities with laments that

contain nanomaterials [Azimi et al. 2016; Dunn et al. 2020a; Kim et al. 2015; NIOSH 2020a;

Stefaniak et al. 2017a; Steinle 2016; Stephens et al. 2013; Yi et al. 2016].

Exposure during post-printing can be decreased by cleaning or nishing a printed object inside a

containment (enclosed) system, wearing personal protective equipment (PPE) including appro-

priate gloves, changing printer laments, and scraping the build plate with hand tools [Azimi et

al. 2016; Kim et al. 2015; NIOSH 2020a; Steinle 2016; Stephens et al. 2013; Yi et al. 2016].

6 | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

3.4 Maintenance and cleaning

Maintenance and cleaning (including housekeeping) are work activities that can have variable

potential for exposure based on the type of printing being done. Examples of activities with higher

potential for inhalation and skin exposures include cleaning the printer head/build plate with solvents,

and maintenance of the printer [NIOSH 2020a,b]. Preventative maintenance in these printers may

also expose workers and users to the print materials, laser, electrical, and robotic hazards.

Examples of work activities with lower potential for exposure include changing the lament(s),

general housekeeping, and collecting waste [NIOSH 2020a].

3.5 Emissions

Polymer feedstock materials can release ultrane particles (< 100 nm diameter) and volatile and

semi-volatile organic compounds (VOCs) if suciently heated [Azimi et al. 2016; Bharti and Singh

2017; Du Preez et al. 2018; Kim et al. 2015; Mooreeld-Lang 2014; Stefaniak et al. 2017a,b, 2018,

2019a,b,c; Stephens et al. 2013; Yi et al. 2016; Zhang et al. 2017]. Exposures to ultrane particles and

VOCs in combination have been associated with adverse respiratory (asthma; cough; itchiness of eyes,

nose, and throat) and cardiovascular health eects (hypertension) [Chan et al. 2018; Donaldson et al.

2004; House et al. 2017; Rumchev et al. 2007; Stefaniak et al. 2017b].

Research has shown that emissions generated from 3D printing processes depend on the type

of 3D printing lament or resin used. Furthermore, the lament material, coloration, extruder

temperature, and many other factors can inuence particle and VOC emission rates [Deng et al.

2016; Dunn et al. 2020a,b; Du Preez et al. 2018; Floyd et al. 2017; Hall et al. 2019; Kim et al.

2015; Stabile et al. 2017; Stefaniak et al. 2017a,b, 2018, 2019a,b,c; Stephens et al. 2013; Yi et

al. 2016; Zhang et al. 2017]. Printing with engineered nanomaterial-containing laments can

emit nanomaterial-containing, ultrane particulate matter [Stefaniak et al. 2018].

Stefaniak et al. [2019a] evaluated emissions from vat photopolymerization printers and determined

they released particles and organic vapors during operation at levels similar to or exceeding those of

other types of 3D printing processes. e average particle and VOC emission yields were signi-

cantly higher and particle sizes were signicantly smaller for DLP-type printers compared with

SLA-type printers, indicating an inuence of printer technology on emissions. e results from

chemical analyses have shown that emissions included multi-constituent particles composed of

metals such as chromium (Cr), nickel (Ni), iron (Fe), and/or zinc (Zn) [Stefaniak et al. 2019a].

Emission rates found in NIOSH studies using an enclosed chamber with FFF printers were com-

parable to those of other published studies using similar 3D printing materials [Azimi et al. 2016;

Mendes et al. 2017; Stefaniak et al. 2017a, 2019c; Steinle 2016; Yi et al. 2016; Zhang et al. 2017].

Note that predicting exposure levels to printer emissions is dicult when based solely on controlled-

environment chamber studies. Workplaces will have many variables, such as room design, ventilation

type and rate, workers or users moving around in the room, and characteristics of the emission

source. A NIOSH eld study determined that background-corrected particulate concentrations in

a conference room with multiple operating FFF printers were much lower than those particulate

concentrations measured from one printer in a test chamber. is was likely due to the conference

room’s greater size and supply air ventilation (12–14 air changes per hour), as compared with the

enclosed test chamber [Dunn et al. 2020b].

Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses | 7

Dierences in FFF printer emissions evaluated in a chamber study primarily depended on the

extruder temperature (higher temperatures resulted in larger emissions), while other conditions

such as lament color and build plate temperature had smaller eects [Zhang et al. 2017].

Filament brand, likely through dierences in trace components in the bulk material, also had a

substantial eect on emissions [Zhang et al. 2017].

Inhaling emissions from certain laments used in the material extrusion processes (FFF printers)

appears to be the primary route of exposure, and this exposure can be associated with adverse

respiratory and cardiovascular health eects [House et al. 2017, Chan et al. 2018, Stefaniak et

al. 2017c]. House et al. [2017] reported a case of work-related asthma in a worker exposed to

emissions while operating material extrusion processes using an ABS lament. In a survey of

workers who were directly involved in the maintenance and use of 3D printers using PLA, ABS,

and nylon laments, 59% (27 of 46) reported respiratory symptoms [Chan et al. 2018]. In an

animal toxicology study, the mean arterial pressure of the test group was 28% higher than the

control group, which indicated that inhalation of emissions was responsible for the observed

acute hypertension [Stefaniak et al. 2017a]. It is unclear if these respiratory and cardiovascular

eects are associated with inhaling emitted particles, organic vapors, or both. Given these emerg-

ing reports of adverse health eects from 3D printing exposures, the magnitude and character-

istics of the emissions and potential exposures need to be understood so that informed decisions

can be made about risk management.

3.6 Solvents

Solvents, including isopropanol, ethanol, methanol, acetone, or chloroform, are sometimes used

in post-printing processes that involve material surface nishing, vapor polishing, support material

removal, or cleaning of the build plate. Many solvents are ammable, and associated vapors can

create an explosion hazard in areas with inadequate ventilation.

Acetone can cause eye and respiratory tract irritation, and chloroform causes depression of the

central nervous system and is identied as possibly carcinogenic [IARC 1999, NIOSH 2007].

Some support materials used in 3D printing are removed by dissolving them in an alkaline (basic)

bath containing a 2% solution of sodium hydroxide at pH 13. Sodium hydroxide is corrosive, can

cause chemical burns, and is also a respiratory irritant [NIOSH 2007].

In addition to relevant safety data sheets (SDSs), the NIOSH Pocket Guide to Chemical

Hazards (https://www.cdc.gov/niosh/docs/2005-149/default.html) is a useful resource on key

information for many chemicals found in the work environment.

3.7 Heat

Temperatures of 190°C to 260°C are typically reached by the FFF extrusion nozzle to soften plastic to

the right consistency for 3D printing [Tyson 2018]. Such temperatures can cause skin burns if users

touch heated components or products before they have time to cool. Skin burns are also common

when 3D printer users try to remove melted plastic from the nozzle while the nozzle is still hot.

Some 3D printers may have heated build platforms that operate between 55°C to 120°C. Heated

build platforms improve print quality by keeping the extruded plastic warm, and thus they prevent

warping. e heated build platform may be hot enough to cause a thermal skin burn.

8 | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

While properly functioning and set, nozzles are usually below the temperature required to create

a re hazard.

3.8 Mechanical risks/moving parts

3D printers contain many moving parts that include stepper motors, pulleys, threaded rods,

carriages, and small fans. Even though most stepper motors do not have enough power to cause

serious injuries, they can still trap a user’s nger, long hair, loose clothing, head covering, or head

scarf. Although many systems isolate the moving parts behind enclosures, caution should be

taken if the printer is opened for maintenance or repair if the unit is not de-energized. See the

OSHA resource “Control of Hazardous Energy (Lockout/Tagout)” (https://www.osha.gov/

control-hazardous-energy).

3.9 Lasers

Vat photopolymerization SLA printers use high-powered lasers (which is an acronym for “light

amplication by stimulated emission of radiation”). ese 3D printers use lasers that present a skin

and eye hazard (FDA Class IIIb or IV), but are considered nonhazardous during printing (FDA

Class I) because the laser is enclosed within the printing chamber. Maintenance of the printer may

expose users to unguarded lasers if the unit is not de-energized. Eects of exposure to unguarded,

energized Class IIIb or Class IV lasers can range from skin burns to irreversible injury to the skin

and eyes, including blindness. Lasers may also present a re hazard. See the OSHA website for

more resources at “Laser Hazards” (https://www.osha.gov/laser-hazards/hazards) and “Control of

Hazardous Energy (Lockout/Tagout)” (https://www.osha.gov/control-hazardous-energy).

3.10 Electrical

Most desktop FFF 3D printers do not have any added electrical safety features beyond regular

internal fuses or external transformers. e voltages in the exposed parts of 3D printers usually

do not exceed 12V to 24V, which is generally considered safe [Selection and use of work practices,

29 CFR 1910.333, 2022]. More generalizable potential hazards may originate from using the

electrical machinery itself. Shock or mechanical injury during maintenance, or malfunction, is

possible if the unit is not de-energized. Sparking electrical equipment can also potentially be a

source of ignition for re or explosion. See the OSHA resource “Control of Hazardous Energy”

(https://www.osha.gov/control-hazardous-energy).

3.11 Noise

High noise levels are typically not a concern with 3D printing, but they should still be consid-

ered a potential hazard. A single 3D printer may not seem noisy, but the noise of several printers

placed together in a room could exceed the NIOSH recommended exposure limit (REL) of 85

dB(A) as an 8-hour time-weighted average [NIOSH 1998]. If a user needs to raise their voice to

be heard within an arm’s length of a printer, the noise level could be a hazard [NCEH 2022]. In

such a case, a hazard assessment is recommended.

Post-processing activities can generate high noise levels and should be considered as potential

hazards when 3D printing. For example, cutting, grinding, and polishing activities typically

generate high noise levels, especially when using power tools.

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3.12 Robotics and automated systems

Automated systems are essential in large-scale 3D printing applications and may also show up in

makerspaces or small businesses. Additional autonomous systems may be further incorporated

for support processes (such as loading feedstock), unloading products, transporting consumables

and products, and in post-processes. Such systems may create or mitigate potential hazards related

to their operations. For instance, a robotic system that helps remove and transport products may

reduce the worker’s ergonomic stress, but it adds the potential hazard of collision with the robot.

Similarly, the ability to operate remotely or autonomously may lower exposures to health and

safety hazards (e.g., hazards from inhalation) at the 3D printer but may increase the rate of user

error (and associated hazards) in the workplace [Roth et al. 2019].

3.13 Take-home exposures

Contamination of work surfaces and areas can lead to exposures. Operators may inadvertently

transport materials beyond the workplace on their shoes, garments, body, and personal items.

is is especially likely for resins and semi- or non-VOCs, but may also occur with metals. ese

exposures may be unanticipated and uncontrolled and may represent a secondary exposure risk

for others (such as family members) who may come into contact with the resins or other chem-

icals from the clothing [Roth et al. 2019]. ese exposures may be of additional concern when

3D printers are used in homes and garages by home-based businesses and hobbyists.

4 Risk Management Considerations

4.1 Risk management plan

e management of makerspaces, schools, libraries, and small businesses should write a compre-

hensive risk management plan for 3D printing. e plan should be readily available and accessible

to all students, patrons, and employees, including temporary employees, contractors, trainees, and

other users. e development of the plan should be a collaborative eort that includes all aected

workers and users. e plan should address all aspects of safely using 3D printers and printing

materials throughout the facility, and it should specify measures that the employer is taking to

protect employees and all users. Since chemicals are used in the forms of polymers, resins, and

solvents, the requirements of the “OSHA Hazard Communication Standard” (https://www.

osha.gov/hazcom) must be met, including providing SDSs and training all aected employees

[Hazard communication, 29 CFR 1910.1200, 2022]. e plan should characterize the hazards

associated with each of the work activities (pre-printing, printing, post-printing, post-processing,

maintenance, and cleaning) and provide best practices and standard operating procedures that

follow the hierarchy of controls (Section 4.2) to reduce the potential hazards.

Health and safety committees can be used to engage workers in developing risk management

plans, including for risks associated with 3D printing. Both employee and management repre-

sentatives should be included on the committee. Helpful guidance can be found on the OSHA

website at “Recommended Practices for Safety and Health Programs” (https://www.osha.gov/

shpguidelines/index.html).

10 | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

4.2 Hierarchy of controls

Health and safety professionals have learned to prioritize certain types of controls over others be-

cause they are eective, practical, and reliable. Such a strategy is known as the hierarchy of controls

(Figure 4). e hierarchy of controls groups actions by their likely eectiveness in eliminating

hazards and/or reducing risks. In most cases, the preferred approach is at the top of the hierarchy.

is approach eliminates or substitutes hazardous materials or processes, or installs engineering

controls to reduce potential exposures. Until such controls are in place, or if they are not eective

or practical, administrative measures and PPE might be needed. NIOSH’s “Hierarchy of Controls”

webpage (https://www.cdc.gov/niosh/topics/hierarchy/) provides more information.

e range of experience by those who operate 3D printers in makerspaces, schools, libraries, and

small businesses reinforces the value of the hierarchy of controls. Approaches near the bottom

of the hierarchy depend heavily on training, compliance, and oversight. Users of varying edu-

cation and skill, or with varying incentives, may not react as much to training and compliance

measures. In contrast, controlling material usage and instituting engineering controls are usually

eective, in addition to being something that printer and facility owners can manage inde-

pendently of the user. Because 3D printing may be a part of the larger mission of makerspaces,

schools, libraries, and small businesses, safety resources should be used eciently.

e recommendations in the following sections are actions that address 3D printing health and

safety in the workplace.

Illustration by NIOSH

Figure 4. Hierarchy of controls (adapted from ANSI/ASSE Z590.3-2011).

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4.3 Elimination/substitution

Eliminating or substituting hazardous processes or materials removes or reduces hazards and

protects users more eectively than other approaches. Eliminating a hazard removes it completely,

such as removing unnecessary, hazardous post-processing steps. Substituting materials could be

done by choosing to build with lower-particle emission materials. Researchers have noted that

printing with ABS material yields higher airborne ultrane particle concentrations than PLA

materials [Byrley et al. 2019; Kim et al. 2015; Stefaniak et al. 2017b, 2019c]. is suggests

substituting PLA for ABS can reduce the hazard from ultrane particulate emissions, provided

printing PLA is within the printer’s specications and otherwise appropriate for the task.

Evaluating the type of material used and deciding whether substitutions can be made can be a

valuable practice. Ongoing research has found that 3D printer emissions can vary just because of

the color of laments. For example, a eld study noted that True Orange PLA lament produced

lower ultrane particle emissions (three to four orders of magnitudes lower) than Slate Gray

impact-resistant PLA lament or True Yellow ABS lament [Dunn et al. 2020b]. e True Orange

PLA also produced lower ultrane particle emissions than laments tested in other 3D printing

studies [Azimi et al. 2016; Mendes et al. 2017; Stefaniak et al. 2017b; Steinle 2016]. Emission

rates for True Orange PLA were also at least three orders of magnitude lower than those measured

during a study by Stefaniak et al. [2017b] of eight dierent PLA and ABS laments. Where emis-

sions data are available for feedstocks of varying color and materials, designers, managers, and users

should consider their options to minimize emissions.

4.4 Engineering controls

Engineering controls reduce user exposures by removing the hazard from the process or by placing

a barrier between the hazard and the user. Properly designed, used, and maintained engineering

controls protect users eectively without placing primary responsibility of implementation on

the user. For example, acceptable room ventilation should help remove particles and maintain

a healthy work environment. Based on assessing three makerspaces at a university, Secondo et

al. [2020] recommended a minimum of six air changes per hour (ACH) within the makerspace

and/or using a portable HEPA (high eciency particulate air) lter to lower ultrane particle

concentrations during printer operation. A study by Viitanen et al. [2021] concluded that for

regular or long-time use of desktop 3D printers, the general ventilation specication of three

ACH was not a sucient control measure for ultrane emissions. Some localities may also have

specic codes that require mechanical exhaust in addition to room ventilation.

Engineering controls can also include placing 3D printers inside ventilated enclosures, or

installing printers under a fume hood or next to a local exhaust to provide source control. Such

a strategy is more ecient than general dilution ventilation. NIOSH engineers have evaluated

control of particulate emissions (including ultrane) at the point of generation using local ex-

haust ventilation (LEV) and HEPA ltration [Dunn et al. 2020b, Stefaniak et al. 2019a]. Using

a ltered enclosing hood placed over a 3D printer resulted in a reduction of 97% to 99% of

particle emissions [Hall et al. 2019]. Viitanen et al. [2021] retrotted an enclosure around a 3D

printer and were able to reduce particle emissions by 97%. When a LEV system was attached

to the enclosure and the exhausted air was vented outdoor through a HEPA lter, the reduction

increased to 99% [Viitanen et al. 2021].

12 | Approaches to Safe 3D Printing: A Guide for Makerspace Users, Schools, Libraries, and Small Businesses

Furthermore, NIOSH engineers designed and tested a custom low-cost engineering control to

t one type of a 3D printer (the MakerBot Replicator+ printer) that eectively captured and

reduced printer emissions by at least 98% [Dunn et al. 2020b]. To accomplish this reduction in

particle number concentration, they replaced the existing plastic cover that supplied cooling air

from three directions to the extruder with a NIOSH-designed print head capture hood. is print

head was 3D printed. e hood supplied cooling air in only one direction (Figure 5). In addition,

NIOSH engineers added a hose connection and an expanded slot for air suction to the NIOSH

capture hood (Figure 6). ey measured emissions in a conference room with 20 printers operating

simultaneously, each equipped with LEV (Figure 7). e use of this engineering control reduced

the peak particle concentrations (size ranging from 10 to 420 nm in diameter) from greater than

20,000 particles per cubic centimeter (p/cm

) to less than background (1,000 p/cm

). When

equipped with a HEPA and charcoal lter, this low-cost control could potentially be retrotted

onto other 3D printer brands and models to reduce both particle and VOC emissions.

Figure 5. 3D-printed replacement extruder cover to capture and exhaust ultrafine particles

[Dunn et al. 2020b].

Illustrations and Photos by NIOSH

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