Nano Particles--Giga Benefits, Giga Risks

Stephen H. Unger
April 4, 2012

Over the past decade, applications of nano technology, principally nano particles, have been proliferating at an amazing rate. Consumer products such as sunscreens, stain-proof fabrics, and scratch-proof eyeglasses, industrial applications such as more durable concrete and stronger steel, medical applications such as the use of nanotubes to deliver medication to cancer cells, are under development or already in use [Trafton]. The use of carbon nanotubes may very well lead to more compact, more efficient integrated circuits. Nano particles are even being incorporated in food and candy [Feder]. Many hundreds of products exploiting nano technology are on the market, and annual sales of such products are in the tens of billions of dollars [SCENIHR].

Unfortunately, the same properties that make nano particles so useful are also potentially harmful in many situations. The small size of nano particles allows them to penetrate various barriers in our bodies, including our skin, that normally screen out substances that would be harmful in the wrong place. The enhanced activity factor that is a consequence of the very large surface area of a quantity of nano materials may make a substance that is harmless in non-nano form dangerous in the form of nano-sized particles. What risks are associated with nano technology? How are they being handled now? How should they be dealt with?

What Could Go Wrong?

Nano particles are generally defined as having diameters between 1 and 100 nano meters (nm). For a given mass of a substance, the smaller the particles, the larger the total surface area. This is a major factor defining the properties of nano particles. The relatively very large surface area makes them much more prone to react physically and chemically with other matter. In addition, being so small, they can pass thru barriers that would screen out larger particles.

The most obvious problem associated with nano particles is that, regardless of their intended application, many will escape to the atmosphere around us and from there may be inhaled and wind up in our lungs. Because of the resemblance of some of these particles (such as carbon nanotubes) to the asbestos fibers that have caused so much grief, this is a very plausible concern [Waters][Bradley].

Nano particles in sunscreen lotions can pass thru skin [Nanowerk]. Nano particles incorporated in food or candy could migrate from mouth, throat. or stomach to other internal organs [Weir][Ju]. Inhaled particles could pass out of lungs possibly into the bloodstream, and from there to other organs, including our brains.

The extent to which particles can penetrate various biological barriers, and the consequences of their presence in various organs obviously varies with the properties of the particles and barriers, and with the nature of the organs [Glover][Karn]. There are indications that some of these factors vary from person to person, and that some effects may be different for children. In addition to possible direct harms to humans, nano particles that, thru various means migrate to the general environment, may also harm various species of animal and vegetable life[Torresdey][ILSR]. The possible cumulative effects of exposure over a period of years or decades, is yet another complicating factor in assessing dangers.

What is Being Done About Possible Harms?

Numerous studies have been made to assess the biological and medical effects of various kinds of exposure to a variety of types of nano particles. These include laboratory experiments on animals and on human tissue, and epidemiological studies. The results clearly indicate that there are biological effects attributable to exposure to nano particles. Many of the results indicate harm. But these conclusions are not officially accepted by regulatory agencies, usually on the ground that tests did not involve enough subjects.

To prove that a particular nano particle application is harmful to humans would, in general, require prospective studies involving tens of thousands of people, backed up by extensive laboratory work to pinpoint the precise mechanism producing serious damage. Since it is often the case that biological harm results only after many years of exposure, it might take decades to build an airtight case against a particular application.

The use of nano particles as such is not regulated in the US, and there are no laws or regulations requiring products containing nano particles to be so labeled [Wikipedia-R]. The kind of pre-market product testing taking place currently is unlikely to uncover harmful effects that are not obvious and short-term [Schneider].

The Great Experiment

We are all subjects of a great experiment, as hundreds of nano-based substances are being produced, sold, used by people, and released into the environment. Unfortunately, while vast numbers of experimental animals (people) are being used, the experiment is not controlled, and data is not being systematically collected, processed, analyzed, and reported. As has been the case for many hazardous materials (e.g., asbestos and lead), workers processing them are often the first to suffer [Smith].

There are substantial benefits of many of the nano technology applications, and a lot of money is being made. Doubtless this accounts for the prevailing attitude that it is OK to market a product unless there is obvious evidence of immediate and substantial harm. This view is implicit in statements by a scientist who, in the course of reporting on clear evidence of a variety of ways in which carbon nanotubes, such as those now coming into use in electronic devices can be harmful, says, "Lots of work needs to be done before we warn people about toxicity" [Schreier].

This reckless attitude that a product is innocent until proven guilty beyond reasonable doubt is not confined to the realm of nano technology. It characterizes the general approach taken by all US regulatory agencies. Consider how it took decades before any action at all was taken to limit the harm done by such deadly products as tobacco, asbestos, and lead [Unger-K].

A case can be made that, if standards are set too high with respect to the safety of products, there will be several detrimental effects. An obvious one, is that really thoro tests to ensure that a product is absolutely safe would be very costly if applied to all products. Furthermore, it would take much longer to obtain approval for a new product, and this would deprive people of the benefits of the product for an extended period. Especially if the product is one that is inherently beneficial to individuals and to the environment, excessive delay would in itself harm people and/or the environment.

But this argument is far from justifying a policy allowing wide dissemination of any product that has not been clearly shown to be immediately harmful. Where very large numbers of people would be at risk if a product turned out to be harmful, perhaps over a long period of usage, or if a product is likely to be widely dispersed in the environment, an attitude of guilty until proven innocent would be more appropriate. That is, a product that, if made generally available so that millions of people would be exposed to it, either directly thru their use, or indirectly as result of other people's usage, should, prior to general usage, be shown to be safe beyond reasonable doubt. (This might be considered an approximate statement of what is termed "The precautionary principle" [Wikipedia-P].)

An example would be sunscreen lotion using nano particles. Various scientists have reported on experiments indicating that nano particles used in sunscreen products can get into various organs of our bodies, and that there are plausible mechanisms whereby this can be damaging. The FDA's recently updated regulations concerning sunscreen say nothing about nano particles [Nanowerk]. They do not even require that such products using nano versions of such compounds as titanium dioxide be so-labeled. So consumers do not even have the option of making their own decisions as to whether to "go nano". It appears that the presumption that such sunscreens are harmful has at least as much scientific backing as the assumption that that they are safe.

Note that this is not a case where some huge health benefit might compensate for an increased risk. Apparently the big advantage of the nano versions is that they are transparent, and so do not mar the appearance of sun bathers. It is also important that people who choose not to use nano-based lotions may also be exposed to the particles as a result of the materials getting into the water in which both users and nonusers are swimming.

This last point typifies situations that undermine the argument that freedoms would be infringed if health regulations prevented people from choosing to use possibly risky substances. This is in addition to the point that, absent protective regulations, we would have to study the scientific literature with respect to each of the dozens of items that we purchase every week, in order to make intelligent judgments as to risk-benefit ratios. And even then, we probably wouldn't be able to make good calls, as few, if any, products have been investigated thoroughly.

The following paragraph from a 2006 NY Times article provides some insight as to how far we are from being adequately protected against hazardous materials.

F.D.A. officials said last week that treating every new nanotechnology product that consumers swallow as a food additive might compromise the agency's mandate to foster innovation and might not be within its authority. Such a move would also be hobbled by the lack of agreement on safety testing standards for the wide range of nanoscale innovations in the pipeline. In addition, the agency lacks the staff to handle that scale of oversight.

What Would Make Sense?

Nano technology, in addition to promising great benefits, poses a major threat to the environment and to the health of the public. But there are many other substances that are also potentially dangerous and have not been properly tested. These, via poorly understood mechanisms, may contribute to or cause any number of diseases, some life threatening, others debilitating in various ways. In addition to cardiovascular ailments, diabetes, and cancer, we are seeing increasing problems involving our hormonal, reproductive, and immune systems [Kristof]. There is substantial research linking many of these problems to exposure to substances that are relatively new in common use. Some new developments pose major, but poorly understood, threats to the environment [Dana].

It is unreasonable to expect individuals to make intelligent decisions on their own about whether the expected benefits of various products are worth the unknown risks involved in using them. Only a few hundred of the over 80,000 chemicals commercially used in the US have been tested for harmful effects, and these tests are generally not very thoro. E.g., long term effects are seldom considered, and the consequences of simultaneous exposure to plausible combinations of substances are not usually studied.

The situation is aggravated by the imposition of secrecy. On commercial grounds, companies commonly withhold information about the chemical composition of many of their products [Layton]. Laws and regulations governing regulatory agencies have been written to accommodate such constraints. This alone makes it almost impossible for these agencies to function effectively. The whole point of our patent system is to eliminate just this sort of secrecy, which, in addition to interfering with mechanisms for protecting the public health, also impedes progress in science and technology [Unger-P].

In a well run society, one should be able to assume that, if a product is on the market, then it is safe to use, and will (when properly used) not endanger anyone or degrade the environment. Exceptions might be justified in cases where use of a product confers unique benefits that might justify substantial risks. In such cases, the risks and benefits should be clearly stated, so that those who would be at risk can choose wisely.

Doing a proper job of testing the huge number of substances already in use would require a massive effort that would be enormously expensive. The alternative is to risk major disasters, and multiple problems that would affect, directly or indirectly, just about everybody. We can't afford not to do it [Unger-F].

In order to do a passable job clearing up the huge backlog of virtually untested materials, much less keeping up with perhaps 500 new chemicals coming into use annually, the budgets for such agencies as the FDA and the EPA would have to be increased by an order of magnitude. While this is would be an enormous and ongoing expense, it would be amply justified by the extent to which it would safeguard the American people against serious dangers [Unger-R]. Consider, for example, the thousands of people killed, and tens of thousands made seriously ill, by just one drug, the painkiller Vioxx, that was allowed on the market because, apparently, it was not ruled by the FDA to be dangerous beyond reasonable doubt [Unger-S].

Can we afford to spend what it would take obtain this protection? Perhaps effective safeguards against the proliferation of dangerous substances should be considered in the same category as such expensive governmental functions as police protection against violent criminals, or military forces for national defense against foreign foes.


Simon Bradley, "Titanium dioxide (TiO2) nanoparticles and lung inflammation.", Hawkes' Health Forum, Jan 20, 2011

Genya V. Dana, Todd Kuiken, David Rejeski, Allison A. Snow "Synthetic biology: Four steps to avoid a synthetic-biology disaster", Nature, March 1, 2012

Barnaby J. Feder, "Engineering Food at Level of Molecules", NY Times, October 10, 2006

Gail Glover, Ryan Yarosh, "Researchers show influence of nanoparticles on nutrient absorption",, March 8, 2012

ILSR, "Bioplastics and Nanotechnology", Institute for Local Self-Reliance,

Anne Ju, "Nanoparticles in food, vitamins could harm human health", Cornell Chronicle Online, Feb. 16, 2012

Barbara Karn, H. Scott Matthews, "Nano particles Without Macroproblems", IEEE Spectum, September 2007

Nicholas D. Kristof, "Do Toxins Cause Autism?", NY Times, February 24, 2010

Lyndsey Layton, "Use of potentially harmful chemicals kept secret under law", Washington Post, January 4, 2010

Nanowerk, "New FDA sunscreen rules called blind to nanotechnology", Nanowerk News, June 2011

SCENIHR, "What are the uses of nanoparticles in consumer products?", European Health and Consumer Protection Directorate, 2006

Andrew Schneider, "EPA's internal watchdogs says agency is unable to protect the public from nanomaterial",, January 10, 2012

Jason Schreier, "Nanoparticles Mimic Asbestos in Danger to Humans", InnovationNewsDaily, September 20, 2011

Rebecca Smith, "Nanoparticles used in paint could kill, research suggests", Telegraph (UK), Aug 19, 2009

Jorge Gardea-Torresdey, "Providing Safe Foods: Safety of nanoparticles in food crops is still unclear", American Chemical Society, August 22, 2011

Anne Trafton, "Delivering a potent cancer drug with nanoparticles can lessen side effects", MIT News , January 11, 2011

Stephen H. Unger-S, "Safety Last—Corporate Profits First", Ends and Means, September 29, 2010

Stephen H. Unger-K, "Pioneer Killer Products: Asbestos, Lead, and Tobacco", Ends and Means, August, 14, 2010

Stephen H. Unger-R, , "Regulating the Invisible Hand: A Contradiction?", Ends and Means, January 15, 2008

Stephen H. Unger-P, "The Patent Game: Multiple Monopoly", Ends and Means, September 8, 2007

Stephen H. Unger-F, , "The Need for People-Friendly Research & Development", Ends and Means, May 4, 2009

Ann-Marie Waters, "Nanoparticles—As Deadly As Asbestos?", Mesothelioma Cancer & Lung Disease, March 21, 2010

Alex Weir, Paul Westerhoff, Lars Fabricius, Kiril Hristovski, Natalie von Goetz, "Titanium Dioxide Nanoparticles in Food and Personal Care Products", Environmenbtal Science & Technology, January 18, 2012

Wikipedia-R, "Regulation of nanotechnology", Wikipedia, January 2012

Wikipedia-P, "Precautionary principle", Wikipedia, February 9, 2012

Comments can be sent to me at unger(at)cs(dot)columbia(dot)edu

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