Approaches to Safe Nanotechnology

104 Pages·2009·1.56 MB·English

Approaches to Safe
Nanotechnology
Managing the Health and Safety Concerns
Associated with Engineered Nanomaterials
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
National Institute for Occupational Safety and Health
Photo Credits:
Nanotrees, Ghim Wei Ho and Professor Mark Welland, Nanostructure Center, University of
Cambridge
Approaches to Safe Nanotechnology
Managing the Health and Safety Concerns
Associated with Engineered Nanomaterials
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
National Institute for Occupational Safety and Health
This document is in the public domain and may be freely
copied or reprinted.
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Foreword
Nanotechnology—the manipulation of matter on a near-atomic scale to produce new structures,
materials, and devices—offers the promise of unprecedented scientifc advancement for many sec-
tors, such as medicine, consumer products, energy, materials, and manufacturing. Nanotechnology
has the power not only to improve existing technologies, but to dramatically enhance the effective-
ness of new applications.
Research on the potential applications of nanotechnology continues to expand rapidly worldwide.
New nanotechnology consumer products emerge at a rate of three to four per week. Over the course
of the next decade, nanotechnology could have a $1 trillion impact on the global economy and em-
ploy two million workers—half of them residing in the U.S.
While nanomaterials present seemingly limitless possibilities, they bring with them new challeng-
es to understanding, predicting, and managing potential safety and health risks to workers. The
National Institute for Occupational Safety and Health (NIOSH) remains committed to protecting
workers now and in the future, as nanotechnology applications and uses expand.
As part of these efforts, in October 2005, NIOSH released for public comment the draft document,
Approaches to Safe Nanotechnology: An Information Exchange with NIOSH. Based on feedback
received, NIOSH revised and updated the document in July 2006 and sought further public com-
ment. This draft report has been widely cited, and the fnal version of the report should serve as a
vital resource for stakeholders (including occupational safety and health professionals, researchers,
policy makers, risk assessors, and workers in the industry) who wish to understand more about the
safety and health implications of nanotechnology in the workplace.
With the publication of the Approaches to Safe Nanotechnology document, NIOSH hopes to: raise
awareness of the occupational safety and health issues involved with nanotechnology; make recom-
mendations on occupational safety and health best practices in the production and use of nanoma-
terials; facilitate dialogue between NIOSH and its external partners in industry, labor and academia;
respond to requests for authoritative safety and health guidelines; and, identify information gaps
and areas for future study and research.
As our knowledge of nanoscience increases, so too will our efforts to provide valuable guidance on
the safe handling of nanoparticles and for protecting the lives and livelihoods of nanotechnology
workers.
Christine M. Branche, Ph.D.
Acting Director, National Institute
for Occupational Safety and Health
Centers for Disease Control and Prevention
Approaches to Safe Nanotechnology iii
Executive Summary
N - nanopaarticles and measures that can be n o t e c h n o l o g y h a s t h e p o t e n t i a l t o d r a
m taken toa minimize workplace exposures. t i c a l l y i m p r o v e t h e e f f e c t i v e n e s s o f a
n - Followiung is a summary of fndings and key m b e r o f e x i s t i n g c o n s u m e r a n d i n d u s
t recommr endations. i a l p r o d u c t s a n d c o u l d h a v e a s u b s t a n t i a l
i - m p a c t o n t h e d e v e l o p m e n t o f n e w p r o d
u c t s i n a l l s e c t o r s , r a n g i n g f r o m d i s e a s e
Potential Health Concerns
d i a g n o s i s a n d t r e a t m e n t t o e n v i r o n m e n t a l
r e m e d i a t i o n . B e c a u s e o f t h e b r o a d r a n g e o f
• The potential for nanomaterials to en-
p o s s i b l e n a n o t e c h n o l o g y a p p l i c a t i o n s , c o n -
ter the body is among several factors
t i n u e d e v a l u a t i o n o f t h e p o t e n t i a l h e a l t h
that scientists examine in determining
r - i s k s a s s o c i a t e d w i t h e x p o s u r e t o n a n o m a
whether such materials may pose an oc-
t - e r i a l s i s e s s e n t i a l t o e n s u r e t h e i r s a f e h a n
cupational health hazard. Nanomateri-
d - l i n g . E n g i n e e r e d n a n o p a r t i c l e s a r e m a t e r i
als have the greatest potential to enter
a l s p u r p o s e f u l l y p r o d u c e d w i t h a t l e a s t o n e
the body through the respiratory sys-
d i m e n s i o n b e t w e e n 1 a n d 1 0 0 n a n o m e t e r s .
tem if they are airborne and in the form
*
N a o n f o t p e a n r t e i x c h l i e b s i t u n i q u e p h y s i c a l
of respirable-sized particles (nanopar-
a n d c h e m i c a l p r o p e r t i e s t h a t i m p a r t s p e c i f c
ticles). They may also come into contact
c - h a r a c t e r i s t i c s e s s e n t i a l i n m a k i n g e n g i
with the skin or be ingested.
n e e r e d m a t e r i a l s , b u t l i t t l e i s k n o w n a b o u t
w • Bahsed on results from human and ani- a t e f f e c t t h e s e p r o p e r t i e s m a y h a v e o n
h mual studies, airborne nanoparticles can m a n h e a l t h . R e s e a r c h h a s s h o w n t h a t t h e
p beh inhaled and deposit in the respira- y s i c o c h e m i c a l c h a r a c t e r i s t i c s o f p a r t i c l e s
c - toary tract; and based on animal stud- n i n f u e n c e t h e i r e f f e c t s i n b i o l o g i c a l s y s
t iees, nanoparticles can enter the blood m s . T h e s e c h a r a c t e r i s t i c s i n c l u d e p a r t i c l e
s stiream, and translocate to other organs. z e , s h a p e , s u r f a c e a r e a , c h a r g e , c h e m i c a l
p r o p e r t i e s , s o l u b i l i t y , o x i d a n t g e n e r a t i o n
• Experimental studies in rats have shown
p - o t e n t i a l , a n d d e g r e e o f a g g l o m e r a t i o n . U n
that equivalent mass doses of insolu-
t i l t h e r e s u l t s f r o m r e s e a r c h s t u d i e s c a n f u l l y
ble incidental nanoparticles are more
e l u c i d a t e t h e c h a r a c t e r i s t i c s o f n a n o p a r t i c l e s
potent than large particles of similar
t h a t m a y p o s e a h e a l t h r i s k , p r e c a u t i o n a r y
composition in causing pulmonary in-
m e a s u r e s a r e w a r r a n t e d .
fammation and lung tumors. Results
N froIm in vitro cell culture studies with O S H h a s d e v e l o p e d t h i s d o c u m e n t t o
p simr ilar materials are generally support- o v i d e a n o v e r v i e w o f w h a t i s k n o w n
a iveb of the biological responses observed o u t t h e p o t e n t i a l h a z a r d s o f e n g i n e e r e d
in animals.
*In an attempt at standardization of terminology, the In-
• Experimental studies in animals, cell
ternational Organization for Standardization-Technical
cultures, and cell-free systems have
Committee 229 has used the term nanomaterial to describe
engineered nanoparticles. shown that changes in the chemical
Approaches to Safe Nanotechnology v
Executive Summary
composition, crystal structure, and size are unlikely to pose a risk of exposure
of particles can infuence their oxidant during their handling and use as ma-
generation properties and cytotoxicity. terials of non-inhalable size. However,
some of the processes used in their pro-
• Studies in workers exposed to aerosols
duction (e.g., formulating and applying
of some manufactured or incidental
nanoscale coatings) may lead to expo-
microscopic (fne) and nanoscale (ul-
sure to nanomaterials, and the cutting
trafne) particles have reported adverse
or grinding of such products could re-
lung effects including lung function
lease respirable-sized nanoparticles.
decrements and obstructive and fbrot-
ic lung diseases. The implications of • Maintenance on production systems (in-
these studies to engineered nanoparti- cluding cleaning and disposal of materi-
cles, which may have different particle als from dust collection systems) is likely
properties, are uncertain. to result in exposure to nanoparticles if
deposited nanomaterials are disturbed.
• Research is needed to determine the
key physical and chemical character- • The following workplace tasks can in-
istics of nanoparticles that determine crease the risk of exposure to nanopar-
their hazard potential. ticles:
— Working with nanomaterials in
Potential Safety Concerns liquid media without adequate
protection (e.g., gloves)
• Although insuffcient information ex-
ists to predict the fre and explosion — Working with nanomaterials in
risk associated with powders of nano- liquid during pouring or mixing
materials, nanoscale combustible ma- operations, or where a high de-
terial could present a higher risk than gree of agitation is involved
coarser material with a similar mass
— Generating nanoparticles in non-
concentration given its increased parti-
enclosed systems
cle surface area and potentially unique
properties due to the nanoscale. — Handling (e.g., weighing, blend-
ing, spraying) powders of nano-
• Some nanomaterials may initiate cat-
materials
alytic reactions depending on their
composition and structure that would — Maintenance on equipment and
not otherwise be anticipated based on processes used to produce or fabri-
their chemical composition. cate nanomaterials and the clean-
ing-up of spills and waste material
containing nanomaterials
Working with Engineered
Nanomaterials — Cleaning of dust collection systems
used to capture nanoparticles
• Nanomaterial-enabled products such as
nanocomposites, surface-coated mate- — Machining, sanding, drilling, or oth-
rials, and materials comprised of nano- er mechanical d isruptions of mate-
structures, such as integrated circuits, rials containing nanoparticles
vi Approaches to Safe Nanotechnology
Executive Summary
Exposure Assessment and for improvement of engineering con-
trols and work practices.
Characterization
• Until more information becomes avail-
Precautionary Measures
able on the mechanisms underlying
nanomaterial toxicity, it is uncertain what
• Given the limited amount of informa-
measurement technique should be used
tion about health risks that may be as-
to monitor exposures in the workplace.
sociated with nanomaterials, taking
Current research indicates that mass and
measures to minimize worker exposures
bulk chemistry may be less important
is prudent.
than particle size and shape, surface area,
and surface chemistry (or activity) for • For most processes and job tasks, the
some nanostructured materials. control of airborne exposure to nano-
aerosols can be accomplished using a
• Many of the sampling techniques that
variety of engineering control tech-
are available for measuring airborne
niques similar to those used in reduc-
nanoaerosols vary in complexity but can
ing exposure to general aerosols.
provide useful information for evaluat-
ing occupational exposures with respect • The implementation of a risk manage-
to particle size, mass, surface area, num-
ment program in workplaces where ex-
ber concentration, and composition.
posure to nanomaterials exists can help
Unfortunately, relatively few of these
to minimize the potential for exposure
techniques are readily applicable to rou-
to nanoparticles. Elements of such a
tine exposure monitoring. NIOSH has
program should include the following:
initiated exposure assessment studies in
workplaces that manufacture or use en- — Evaluating the hazard posed by the
gineered nanoparticles (see Appendix nanomaterial based on available
Nanoparticle Emission Assessment Tech- physical and chemical property
nique for Identifcation of Sources and data, toxicology, or health-effects
Releases of Engineered Nanomaterials). data
• Regardless of the metric or measurement — Assessing the worker’s job task to
method used for evaluating nanoaerosol determine the potential for expo-
exposures, it is critical that background sure
nanoscale particle measurements be
— Educating and training workers in
conducted before the production, pro-
the proper handling of nanomate-
cessing, or handling of nanomaterials.
rials (e.g., good work practices)
• When feasible, personal sampling is pre-
ferred to ensure an accurate representa- — Establishing criteria and proce-
tion of the worker’s exposure, whereas dures for installing and evaluat-
area sampling (e.g., size-fractionated ing engineering controls (e.g.,
aerosol samples) and real-time (direct exhaust ventilation) at locations
reading) exposure measurements may where exposure to nanomaterials
be more useful for evaluating the need might occur
Approaches to Safe Nanotechnology vii
Executive Summary
— Developing procedures for deter- • Respirators may be necessary when en-
mining the need for and selecting gineering and administrative controls
proper personal protective equip- do not adequately prevent exposures.
ment (e.g., clothing, gloves, respi- Currently, there are no specifc limits
rators) for airborne exposures to engineered
nanoparticles although occupational
— Systematically evaluating expo-
exposure limits exist for some larger
sures to ensure that control mea-
particles of similar chemical compo-
sures are working properly and
sition. It should be recognized that
that workers are being provided
exposure limits recommended for non-
the appropriate personal protec-
nanoscale particles may not be health
tive equipment
protective for nanoparticle exposures
• Engineering control techniques such as (e.g., the OSHA Permissible Exposure
source enclosure (i.e., isolating the gen- Limit [PEL] for graphite may not be a
eration source from the worker) and lo- safe exposure limit for carbon nano-
cal exhaust ventilation systems should be tubes). The decision to use respiratory
effective for capturing airborne nano- protection should be based on profes-
particles. Current knowledge indicates sional judgment that takes into account
that a well-designed exhaust ventilation toxicity information, exposure mea-
system with a high-effciency particulate surement data, and the frequency and
air (HEPA) flter should effectively re- likelihood of the worker’s exposure.
move nanomaterials. While research is continuing, prelimi-
nary evidence indicates that NIOSH-
• The use of good work practices can
certifed respirators will be useful for
help to minimize worker exposures
protecting workers from nanoparticle
to nanomaterials. Examples of good
inhalation when properly selected and
practices include cleaning of work ar-
ft tested as part of a complete respira-
eas using HEPA vacuum pickup and
tory protection program.
wet wiping methods, preventing the
consumption of food or beverages in
workplaces where nanomaterials are Occupational Health
handled, providing hand-washing fa- Surveillance
cilities, and providing facilities for
Occupational health surveillance is an essen-
showering and changing clothes.
tial component of an effective occupational
• No guidelines are currently available on safety and health program. The unique phys-
the selection of clothing or other ap- ical and chemical properties of nanomateri-
parel (e.g., gloves) for the prevention als, the increasing growth of nanotechnology
of dermal exposure to nanoaerosols. in the workplace, and information suggesting
However, some clothing standards in- that exposure to some engineered nanomate-
corporate testing with nanometer-sized rials can cause adverse health effects in labo-
particles and therefore provide some in- ratory animals all support consideration of
dication of the effectiveness of protec- an occupational health surveillance program
tive clothing. for workers potentially exposed to engineered
viii Approaches to Safe Nanotechnology