Ten things everyone should know about nanotechnology safety

by Andrew Maynard on August 29, 2009

Asked to conclude the Fourth International Conference on Nanotechnology, Occupational and Environmental Health in Helsinki this year, I rather rashly came up with the above title for my talk—thinking that I would find inspiration in the multitude of new research on nanotech safety being presented at the meeting.

As it turns out, events conspired against me and I ended up unavoidably missing most of the conference!

Faced with the tricky task of wrapping up a meeting that I had been embarrassingly absent from, I decided to share a rather more personal perspective on nanotechnology safety—my own reflections on things I think people should know.

This list is far from complete, and is heavily biased towards workplace safety.  And given that it was prepared for a crowd of conference attendees who were most likely maxed out on nano and more interested in where the nearest bar was, it’s a little light on detail.

Nevertheless, it is hopefully interesting and informative, and causes at least one person other than myself to stop and think afresh about how to ensure safety in the face of a new and rapidly developing technology.

So without further ado, and in reverse order, here is my highly subjective list of ten things everyone should know about nanotechnology safety…

10.  There’s no such thing as “nanotechnology safety”

Actually, this isn’t quite true.  Nanotechnology safety is clearly an important and legitimate goal.  It’s just that when you get down to the business of protecting people and the environment, the big idea of “nanotechnology” can become more of a hindrance than a help.

These are just two traps that discussing “nanotechnology safety” can open up:

First, we have the problem of definitions.  If we are going to discuss “nanotechnology safety,” we need to know what we are talking about.  Unfortunately, the generally accepted definition of nanotechnology—“the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications” is what the US National Nanotechnology Initiative uses—is one of expedience, not of science.  It serves the purpose of stimulating new research and technology innovation in an exciting new area brilliantly.  But it doesn’t clearly define a set of products and processes that have common and specific safety issues; and it was never intended to.

As a result, attempts to apply the generally accepted definition of nanotechnology to material and product safety ends up in a messy mismatch.  Materials that are probably benign come under suspicion, while others that we should be worried about potentially slip the net.

Second, there is the problem of generalities.  The products of nanotechnology are infinitely varied; each behaves in a different way and potentially presents a different set of risks.  This is obvious when we think about it.  Comparing the potential benefits and risks of scanning tunneling microscopes, semiconductor chips and smart drugs (for instance) is nonsensical, even though each can legitimately be claimed as a product of nanotechnology.  The trouble is, focusing on “nanotechnology safety” seems to result in rationality by-pass sometimes, leading to the questionable assumption that nanotechnology presents a common set of safety problems, which can be solved by a common suite of safety solutions.

In the extreme, this type of generalization can lead to experiences with one nanotech product being applied to others—safety concerns over titanium dioxide nanoparticles in sunscreens being driven by inhalation studies using carbon nanotubes for instance; or consumers potentially avoiding “nano” branded goods because they heard that “nanotechnology” isn’t “safe.”

Perhaps more to the point though, nanotechnology—like most technologies—is safety-neutral.  It isn’t the technology so much as what is done with it that is important.  Which means that rather than talking about “nanotechnology safety,” it makes a lot more sense to talk about the safe handling, use and disposal of specific materials, products and processes that arise from its application.

9.  We’re living in a post-chemistry world

Having debunked the idea of “nanotechnology safety,” I should really talk about what might be important when it comes to working with and using the products of nanotechnology as safely as possible—because without a doubt, some of its uses will lead to new safety challenges.

One class of products that raises some interesting safety questions is “nanomaterials”—materials engineered at the nanometer-scale so they exhibit scale-specific properties.  These materials are intentionally designed to do what they do because of their physical form, as well as their chemical makeup.  So it seems reasonable to ask whether what they look like at the nanoscale also leads to new safety issues.

Of course, for physical form to be relevant to human health or the environment, the material first has to get to where it can do harm.  For people, this means that chunks of it need to be small enough to be inhaled, ingested, or penetrate through the skin.  No exposure—no harm.

However, for nanomaterials that can get into the body, there will be some cases where their physical form—their size, shape, physical structure—can lead to them being dangerous above certain concentrations.

But here’s the rub.  Over the past fifty plus years, we’ve got used to assessing the likely risks associated with materials by considering their chemistry alone.  As a result we have a bit of a blind spot when it comes to materials that are potentially harmful because of something more than just their chemical composition.

This is a bit of an oversimplification of course.  In the field of occupational health we have had to deal with asbestos and other fibers that cause harm because of their chemistry and their physical form.  And it’s long been recognized that different sized airborne particles present different risks if inhaled.  But these are the exceptions rather than the rule, and there is still a tendency when assessing risks to ignore physical form, or to struggle with what to do with it.

However, as engineered nanomaterials become increasingly sophisticated, this will need to change if we are to work with them safely.  We are living in a post-chemistry world, where functionality and safety depend on more than just what something is made of.  And if we are to ensure the safety of emerging engineered nanomaterials, we need to learn how to survive and thrive in this world.

8.  Current understanding of nanomaterial risks has more holes than a Swiss cheese

So we know that we might need a new perspective on the potential risks associated with engineered nanomaterials and how to manage them.  But here we hit a problem—when it comes to answering questions that seem to be important, there’s a distinct dearth of information.

Quantifying the human health risks (for example) associated with a material—a normal step in ensuring their safe use—requires answers to many questions, including:

  • How can the material enter the body?
  • Where does it go and how does it change once it gets there?
  • What aspects of the material end up causing harm?
  • How much material is needed for serious harm to occur?
  • How should the toxicity of the material be assessed?
  • How will people end up being exposed to the material?
  • How should exposure be measured? And
  • Can exposures be adequately controlled?

When it comes to new nanomaterials, these are just some of the questions we still don’t have complete answers to.  And they only address occupational exposures.  What happens when these same nanomaterials get out into the environment?

If we are going to get a good handle on working safely with engineered nanomaterials and other products based on nanotechnology, these holes will eventually need to be filled.  And as the diversity and sophistication of engineered nanomaterials continues to grow, research into assessing and managing their possible risks will need to be well funded and strategically targeted if it is to keep up.

7.  Engineered nanomaterials are accomplished shape-shifters

It is probably something of an exaggeration to refer to nanomaterials as shape-shifters, but without a doubt, one of the big challenges of ensuring the safety of engineered nanomaterials is that their behavior changes depending on where they are, and where they’ve been.  A freshly minted nanoparticle may have a surface that is crammed full of highly active chemicals.  Ten minutes later, these chemicals may have lost their potency—with a resulting reduction in the material’s ability to cause harm.  Small particles may agglomerate with others to form large particles over time.  Or large agglomerates may separate out into smaller ones once inhaled.  Particles moving through the air might pick up a coating of other chemicals in their vicinity and, if inhaled, will behave differently to “naked” particles.  Nanoparticles in the lungs or blood may become shrouded in specific biological molecules that dictate where they go and how the body responds.  Nanoparticles may be suspended in liquids, compressed into pellets, or embedded in plastics.  Nanotechnology-enabled products may shed material that changes as it moves through the environment, and moves through the environment differently as it changes.  And nano-products disposed of at the end of their life may once again liberate nanomaterials that bear little resemblance to the stuff they were originally made of.

In short, the qualities that make a nanomaterial potentially harmful change over the material’s lifetime.

This complicates matters when it comes to ensuring safety.  Just because a nanoparticle in a workplace is considered safe, doesn’t mean that it will still be safe several steps down the road.  The converse is also true—a nanomaterial that needs to be handled with care in the workplace may be relatively benign after it has been incorporated into a product.

There are no easy answers to dealing with this shifting risk profile.  But one thing is certain: If engineered nanomaterials are to be used safely, their potential for causing harm, and the means to manage this, needs to be considered across their life cycle.

6.  The technology’s new, but that doesn’t make old safety practices redundant

In the face of a new and, in some cases, radically different technology, there is a temptation for imaginations to go into overdrive and assume that these new technologies automatically demand new safety measures.

Fortunately, even though we are facing a nanotechnology safety future that is complex and riddled with holes, we do have some tricks at our disposal for helping to ensure the safer handling of nanomaterials.

It seems that established occupational hygiene practices go a long way to preventing exposures and reducing risks.  Guidance from the US National Institute for Occupational Safety and Health (NIOSH), BSI, the International Standards Organization (ISO) and others makes it very clear that by taking reasonable precautions with how materials are handled, control measures are established and workers are protected, the chances of something untoward happening are reduced substantially—even if hard data on a new material’s toxicity are lacking.

Undoubtedly there will be situations where conventional practices don’t go all the way to ensuring the safe use of nanomaterials—just one more reason why more research is needed. But we do know that airborne nanoparticles can be removed from the air with conventional local exhaust ventilation systems; that air filters do a good job of reducing exposures; and that bad workplace practices increase the chances of harm occurring, whether the materials being handled are nanoscale or not.

So the good news is that we don’t need to throw out decades of experience with working safely with nanomaterials.

On the other hand, it’s probably not a good idea to be complacent—old tricks may work with new technologies, but probably only up to a point.

And just to be clear, there is a world of difference between safe and safer.

5.  Lower exposures mean lower risks

Continuing the theme of old tricks, reducing risks through controlling exposure does seem to be an area where established wisdom has a role to play with engineered nanomaterials.

As a rule of thumb, lowering exposure levels is likely to reduce potential risks from nanomaterials, even in the absence of hard toxicity data.  With few exceptions, the human health risks of materials tend to follow a general trend of increasing response with increasing dose.  There are subtleties here involving the shape of the relationship between dose and response, the period over which effects occur, how dose is measured and whether a dose exists below which no response is observed.  But these aside, most of our experiences with harmful agents—whether gases, liquids or particles—suggest that less stuff means lower risk.

This is helpful when handling new engineered nanomaterials, because we can be reasonably sure that every step towards lowering exposures is a step in the right direction.  It means that equipped with the most basic exposure control technologies and an instrument capable of measuring some aspect of the nanomaterial concentration, potential risks can be reduced.

But helpful as this approach to reducing risk is, there is a problem: how low is low enough?

4.  Measurement without meaning is like a car without an engine

If you measure the concentration of nanoparticles in a workplace—say you measure the number or mass of particles per cubic meter—what does that measurement mean?  And how can you use it to increase safety without impacting unnecessarily on operating costs?

Exposure measurement is a tricky subject.  Numbers—hard data—can be comforting.  But without a clear idea of their relevance, they can also be misleading. A measurement of airborne nanomaterial concentration can be used to reduce exposure, but how far should it be reduced?  Alternatively, measurements can be used to try and eliminate exposure altogether.  But there’s always that lingering doubt that exposures are occurring below the instrument’s detection threshold.  And rather annoyingly, the lower the concentration of material an instrument will detect, and the harder it will be to get a zero reading.

In other words, measurements without the means to interpret and use them are a bit like a car without an engine—pretty, but useless!

The reality is that without guidance on how to interpret and act on them, measurements can cause more problems than they solve—especially if the cost of reducing exposures to some arbitrary level becomes prohibitively expensive.

What would be helpful here is a benchmark against which exposure measurements can be assessed—a reference that enables measurements to be translated into actions.  Where solid risk-related data are available, these benchmarks are the exposure limits set by governments and other organizations familiar to any occupational hygienist.

But what do you do in the absence of such limits?

One option is to take a stab at estimating reasonable benchmark limits, based on the best available information. For instance, in “Nanotechnologies – Part 2: Guide to safe handling and disposal of manufactured nanomaterials,” BSI has recommended a series of rules –of-thumb, based on reasonably well-understood materials, which help establish working benchmark levels for new and untested materials.  The idea is that in the absence of any better information, exposure limits for analogous materials are used as a starting point.

The methodology is rough and ready, and doesn’t sit well with every expert.  But at least it provides a useful way of assigning meaning to measurements; as long at the working benchmark levels do not become set in stone.

3.  When the data run out – innovate!

This question of measuring exposure in the absence of well-established exposure limits is just one part of a larger issue—how do you make smart safety decisions in the absence of good information?

Even if we can use established practiced to lower risks, we are still faced with a barrow-load of unknowns and uncertainties that pull the rug out from under conventional approaches to quantifying and managing risks.  And even if did manage to fill in all the current knowledge-holes, the chances are that we would be facing a whole new set of uncertainties sooner rather than later.

So what do we do – apart from panic?

The answer is: Innovate! More than ever in the future, we will have to rely on new and innovative approaches to managing risks; ones that enable decisions to be made in the absence of hard data.  Something of this was seen in the observation that lower exposures mean lower risks—a concept that enables risks to be reduced even in the absence of toxicology data.  Yet more inventive approaches will be needed if engineered nanomaterials are to be used safely in a world where a science-based understanding of the risks looks increasingly like a Swiss cheese, no matter how hard we try.

Vladimir Murashov and John Howard recently highlighted some possible innovations in the journal Nature Nanotechnology. Writing on essential features for proactive risk management, they discussed a number of ways to manage risk in a data-deficient world.  In particular, they stressed the need to consider “soft” (or qualitative) approaches to assessing and managing risks such as using expert judgment, and control banding.

These recommendations are a good start.  But much more is needed if we are to learn to make smart choices in the face of uncertainty.

2.  It’s good to talk

The adage “a problem shared is a problem halved” is rather a trite one, but it does contain a grain of truth.  Where companies and workers face difficult challenges in ensuring the safety of their workplaces, drawing on the collective wisdom of the community can be a great boon.

In their article, Murashov and Howard stressed is the need for global stakeholder cooperation in ensuring the safe use of engineered nanomaterials.  This makes perfect sense.  Safety shouldn’t be a competitive issue—it’s in everyone’s interest to share information and experiences that will prevent harm to people or the environment. Information sharing encourages faster, better solutions to challenges. It allows smaller outfits to tap into a wealth of experience and expertise that would otherwise be beyond their reach. And it reduces the chances of competitors making a mess of “nanotechnology safety” in a way that undermines the credibility of the technology as a whole.

The good news is that people are talking—not as much as they should perhaps, but at least the lines of communication are open.  The NanOEH2009 conferences is a great example of information sharing, and there are many more—ISO and OECD initiatives for instance, and the work of the International Council On Nanotechnology.

But I wanted to highlight one initiative in particular, in part because I had a small hand in the initial idea, but mainly because I think it has great potential to get the global nanotechnology safety community working together to find solutions to the challenges they face.  And that is the Good Nano Guide.

Designed as a community forum and resource, this is developing into an important place for learning about other people’s experiences of working safely with nanomaterials, and for sharing your own.  As people begin to contribute to it and use it, it could turn into an open-access goldmine for know-how on working as safely as possible with engineered nanomaterials.

1.  People matter

And finally my number one thing that everyone should know about nanotechnology safety—people matter.

This may seem simple, or obvious, but it’s something that can get left out of the equation all too easily.

At the end of the day, human risk research is about protecting people from injury, disease and death, and ensuring a high quality of life.  It isn’t about the buzz of new discovery.  It isn’t about getting rich and famous.  It isn’t about making a profit.  And it isn’t about sustaining ideologies.

All of these have their place, and in many cases are good and important.  But the primary focus of risk research should be the people it ultimately impacts.

This is part of the culture of risk-based research professionals who have come up through schools of public health, government research labs and similar institutions.  It may get buried at times.  But generally there is that recognition that the rewards of the work are more safe and healthy people, and fewer injuries, diseases and deaths.

(It goes without saying that a similar ethos exists for environmental risk research)

But when it comes to nanotechnology risk research, I am concerned by the influx of researchers and decision-makers into the field that don’t come from this culture of focusing on people’s health and safety.

This is a very personal perspective, and I may be wrong.  But it seems that with increasing interest in, and funding available, for nanotechnology-related risk research, there has been a shift in emphasis away from traditional risk-research experts and towards researchers with primary expertise in other areas—chemistry, materials science and drug development for example.

This isn’t necessarily a bad thing.  But it does mean that research programs, strategies and policies are increasingly being influenced by people who lack a professional cultural bias toward focusing on the individuals their work and decisions will affect.

That is not to imply that these people do not care—in many cases, they clearly do.  But without that ingrained culture of putting others first, I wonder whether there is a danger of nanotechnology risk research being driven more by political expediency and the promise of economic gain, and less by the need to protect people.

If this isn’t the case, I am willing to stand corrected.  But if it is, we need to work out how to get people back at the center of the nano-risk enterprise.  This may need some careful thought over where research funding goes and how strategic research decisions are made.   But I suspect it will also rely on the willingness of the emerging nanotechnology safety community to rethink and reaffirm its values.

At the end of the day, despite the clear economic and social justifications, getting nanotechnology “right” will be a hollow achievement if we end up neglecting the very people who will make its success possible.  Let’s hope we don’t.

1 Andréia Azevedo Soares September 2, 2009 at 4:23 am

I enjoyed reading this clear-cut and “humanized” list. As a member of a lay audience, I get the feeling I understood the main issues at stake when it comes to addressing nanotechnology risk safety. This is to say here you have a nice piece of sci-comm. Thanks for that.

PS. I was wondering if there are toxicology data on exposure during pregnancy and embryo development (yes, I know this is a quite delicate subject, and also a difficult one to study since it is impossible to design experiments regarding ethics) . What are the current protocols (if any) for female workers?

2 Andrew Maynard September 2, 2009 at 10:22 am

Thanks Andréia,

I was pleasantly surprised that you thought this worked for a lay audience – I was worried that it was far too long and esoteric for anyone not deeply immersed in nanotechnology to appreciate!

The question of exposure during pregnancy is a critical one, that hasn’t really been explored sufficiently yet. With a new technology and a new set of materials, there’s a tendency to focus initially on mainstream potential health challenges, and neglect more susceptible groups (pregnant women, children, the elderly, the infirm etc.). But it’s often these groups that are more at risk. When it comes to engineered nanomaterials and pregnant women, there have been tentative studies suggesting some types of material could cross the placental barrier – but there is no where near enough information to suggest if and when this might be a serious issue. Something that clearly needs more research.

3 Charles Jordan September 26, 2009 at 8:36 pm

Very interesting and informative article. Safety is of course a concern with nanotechnology but what about all the things that are around us everyday that are of nano size? Car exhausts, clay soil particles in the air, etc. In addition to talking about the safety with the newly manufactured nanoparticles, we should also include that these are already in the air, and have been for many years.

4 John Allen February 1, 2011 at 3:26 pm

I thought that your article was very clear and interesting. I did, however, think there was one basic question – perhaps in quite a different vein – that you did not address. What of areas of nanotechnology being developed which are intended to harm people. These would include various types of weapon systems including biological agents. Do you think that these are possible future threats? A very difficult question but one definately related to human safety. How do you believe these issues should be addressed?

I am posting this in 2011 – perhaps you are not still monitoring comments but, if you are, I would appreciate your thoughts. Thanks

5 Andrew Maynard February 1, 2011 at 3:38 pm

Hi John,

Thanks for the comment – which is an interesting one. I was talking about this very subject just a few days ago, and had to admit that the nano safety community – myself included – have shied away from talking about the use of nanotech in weapons systems. I suspect this is because it isn’t too hard to imagine how the technology can be used to harm people in inventive ways, and I for one feel uneasy about putting new ideas into people’s heads in this area. But at some point, it is a discussion that needs to be had.

6 Carolina Mendoza January 29, 2013 at 8:12 am

Very interesting article. I recently got into the subject of nanotechnology safety and this article helped me a lot, it clarified my ideas. Thanks

7 SC Mehta April 2, 2013 at 1:13 am

I want to know about recent development relating to APPLICATION OF NANOTECHNOLOGY in enhancing chances of fertility of women who could not conceive due to any reason – though normal medical tests conclude normal situation.

Comments on this entry are closed.