Skip to content

Sheep, Goats, and Nanoparticles

2010 February 10

I was a child when introduced to the phrase, “separating the sheep from the goats.” Although the saying has biblical roots, I typically heard it in reference to distinguishing between good and bad, or between high and low value. Recently, I’ve been thinking about it with respect to nanotechnology.

Earlier this year I participated in a public event, and we were asked: “Are nanomaterials safe?” This reasonable question comes up often, sometimes in the negative form, “Are nanomaterials dangerous?” I have begun prefacing my response by asking that we reframe the question.

This is where sheep and goats come in.

Nanoparticles taken as a large group actually seem to be a mixed collection of at least these two ruminants. We could also add cattle, bison, and the odd yak. Many particles are likely to be sheep—beneficial, benign, and obedient to our calls to form an orderly herd. Others are cattle, mostly docile except for the occasional bull who rages when provoked. The bison are the naturally produced nanoparticles, untamed but in harmony with nature. The yaks are particles like dendrimers: hairy and a bit exotic, but valuable to those who know how to use them.

Then there are the goats: particles whose particular characteristics may spell trouble for people or wildlife if not kept under control. Goats can be tamed and very useful. (I’m a big fan of goat cheese.) Yet goats, being goats, are prone to mischief. When I was a kid, I had a Nubian goat as a pet and he was a prankster, sneaking up behind me and gently butting my backside.

The reframed question, then, is not whether nanomaterials in general are safe or dangerous but rather, how we identify the goats and either keep their bad behavior in check or ban them from the barnyard altogether.

To do that, we need to learn what makes a particular nanoparticle troublesome—a goat. Do particles that look like fibers become a problem if they are long, and therefore perhaps more difficult to remove from the lung if inhaled? Are very small particles more likely than larger ones to go places we don’t want them to go (such as into cells) or will they clump together and not get very far?

These are the kinds of questions EPA’s Nanotechnology Research Program is working to address.

Not all of us grew up on farms, but we all know the importance of separating the sheep from the goats.

About the author: Jeff Morris is National Program Director for Nanotechnology in EPA’s Office of Research and Development.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

Please share this post. However, please don't change the title or the content. If you do make changes, don't attribute the edited title or content to EPA or the author.

28 Responses leave one →
  1. Anya permalink
    February 11, 2010

    On the topic of sheep vs goats on a nanoscale, I have an idea that I’d like to explore, but first need to know if I’m waaaay out in left field, and if my ideas are baaaah humbug ….

    1) Has anyone gotten memory polymers down to a sphere/roll that’s oh, only 250 micrometers in diameter?

    2) Can these polymers “self heal” from a hole poked/sliced that’s 5-50 micrometers long/wide?

    3) Can one relax these memory polymers
    a) electrically, then have them spring back together when electricity removed
    b) chemically, after a period of time sitting in the solution?

    4) How strong are these polymers? How much force would it take for something inside the 250 micrometer diameter to “bust” or push out? Would this force change with a small or large overlap in the “roll” ?

    5) Can one eventually dissolve the polymer to get it to relax or fall
    apart, without being too damaging to what is inside?

    Thanks so much!

  2. Mary Lamielle permalink
    February 11, 2010

    Interesting piece on nanotechnology. I’ll be checking out the referenced EPA work. I saw an info commercial advertising food storage containers made using nanotechnology that would allow one to store chicken salad for 20 days. Made me think that even if you could and it was safe, would you really want to?

  3. Al Bannet permalink
    February 11, 2010

    Jeff Morris,

    The potential misuse, perversion and corruption of nantechnology is beyond measure precisely because nanotech is microscopic. The “Alien” films demonstrated graphically the degree of deception possible when a nanotech robot can pass for a physical human being.
    Then, there is all the fantasy nonsense in which terrified persons imagine transferring their memory to a robot and thereby escape death. Are there any laws to protecct the people from such misuse of nanotechnology ( and others I haven’t thought of ? )

  4. armansyahardanis permalink
    February 11, 2010

    I see from the other sides, NASA-EPA&Nanotechnology. NASA as sheep, EPA as goat; need nanotechnology for their mission. Future, the universe needs NASA & EPA for explorer her. NASA needs EPA and EPA supports NASA by her experience in this world. I imagine the others planet are going to similar with the earth future……!!!!!!

  5. Casey permalink
    February 11, 2010

    I am glad to see the EPA is investigating this issue–it is a topic that needs more science behind it. There hasn’t been much public discussion about the safety of nanoparticles even though they are becoming more prevalent in consumer products.

    I think we need more science (1) so we can start taking precautions if warranted, and I suspect some precaution will be warranted, and (2) so we can prevent undue hysteria if it turns out they aren’t so bad.

    Nanoparticles have many potential benefits, so let’s develop a prudent level of regulation before there is cause for a public panic and they become over regulated. And thank you for making the point about different nanoparticles behaving differently–we wouldn’t want to heavily regulate all nanomaterials when only certain classes are hazardous.

  6. Joan permalink
    February 11, 2010

    Your sheep/goat/ruminant analogy has shed a ray of light on a fascinating but complex subject. You could write a book!

  7. Michael E. Bailey permalink
    February 11, 2010

    Nanosciense is one of the corner stones of research in the 21st Century. But, it must be handled with caustion until its environemental impacts are well understood. I can remember the agrichemical boom of the 1960s and the chemical companies emphasing that their products would kill weeds or insects but never talking about the environmental hazards. It only came out how dangerous agrichemicals were after strong federal and environmental laws were passed and major environmental disasters happened. We should research and explore and use nanoscience in our products but should not make the same mistakes with them that we did with agricultural chemicals. Best wishes, MichaelE. Bailey.

  8. jairo permalink
    February 11, 2010

    On topic of sheeps vs goats, I really think noparticles were released to the public, without sufficent study, and without a responsible action from the governments.

  9. Billy Capra permalink
    February 11, 2010

    Your comments show extreme insensitivity to animals by comparing goats to troublesome nanoparticles. A more informed opinion would better serve visitors to the EPA Greenversation blog.

  10. David Mc permalink
    February 11, 2010

    Jeff, my Mom had a Billy goat when she was a little girl. It used to pull her on a cart. She still loves to remember being a little girl, her mischievous goat. What do you had against goats? I’m kidding.That was cute. Oh, and Mom did have a Billy goat.

  11. Jeff Morris permalink
    February 12, 2010

    Thanks for your comment. While the performance characteristics of such products is not a subject of the EPA research program, I am aware of activity to attempt to bring to commercialization shape memory polymers using nanomaterials. See for example the following article:

    Best regards,


  12. David Mc permalink
    February 12, 2010

    “fantasy nonsense”? maybe you just need to design the right processors and add some chemistry (hormones)?.

  13. David Mc permalink
    February 12, 2010

    Billy, It’s a parable for gosh sake. Join the human race.
    We all think goats are cooler than sheep in real life.

  14. Jeff Morris permalink
    February 14, 2010

    Thanks for the comment. The question you ask reflects just the type of discourse that is important for society’s consideration of new technologies. As citizens in a democracy and consumers of products, I think it is important that we raise questions about the desirability of new products. Perhaps the benefits of a particular new product’s capabilities are worth the uncertainties associated with the new technology (since all new technologies carry uncertainties). Or maybe they are not. I don’t have the answer for food storage containers, but I think the best way for society to reach consensus on the desirability of such uses is for all of us to keep the discussion going, as you are helping to do with your comments.

  15. Jeff Morris permalink
    February 14, 2010

    Thank you for the comment. Countries around the world have various legal frameworks for evaluating the safety of materials, including nano-scale materials, that may enter or have entered commerce. Here in the United States we have a number of such laws. Our EPA Nanotechnology White Paper provides a description of how nanotechnology could be addressed under various laws. The White Paper may be found at, under “Resources.” You may also wish to look at the following EPA web site to see how EPA is addressing nanotechnology under the Toxic Substances Control Act:

  16. Jeff Morris permalink
    February 14, 2010

    Thanks for your comments. Of course I was not comparing animals to nanoparticles, but rather using the ages-old saying “separating the sheep from the goats” to illustrate that nanoparticles are not as a group homogeneous, but rather that distinctions must be made between particle types to identify what specific properties of particular particle types have the potential to create unintended environmental consequences.

    As someone who grew up raising many kinds of animals (including the goat referenced in my blog, who by the way lived a long and happy life) and still raises them (within the limits of living in suburban Northern Virginia!), I think I’m pretty informed — at least from the perspective of practical experience — about animals as well as very appreciative of both their inherent worth and value to society. I’m glad to hear that you also appreciate animals.

  17. Jeff Morris permalink
    February 14, 2010

    Thanks for the comment. My Nubian billy goat (we just called him “Goat”) may have been the smartest animal I ever had. (And I’ve had some very smart dogs.) But I never thought of having him pull me on a cart. I’m guessing that the only way I could have gotten him to do it would have been to entice him with one of his favorite foods (such as apples). Thanks again.

  18. Jeff Morris permalink
    February 14, 2010

    Thanks very much for your comment. EPA and NASA have a very good working relationship, and we share information related to our interests in nanotechnology.

  19. Jeff Morris permalink
    February 14, 2010

    Thanks so much for your comments, which from my perspective are very much in line with how we at EPA view nanotechnology. We see the potential for societal (including environmental) benefits of nanotechnology applications, and want to help maximize the benefits society derives from nanomaterials by doing what we can to avoid any adverse unintended consequences of their use in products.

  20. Jeff Morris permalink
    February 14, 2010

    Thanks very much for your comment. I’m glad you liked the blog. My wife always tells me that whenever I get to that book I’ve always wanted to write, that I need to work our two dogs into it. Now it appears that I need to fit in my childhood pet goat!

    There are some good nanotechnology blogs and articles out there that do a nice job of clearly presenting the issues, including those related to the environment — I know they’ve been a big help to me. If you’re interested, the International Council on Nanotechnology (ICON) site is a good starting point: If you go the ICON home page and click on “Resources,” the ICON backgrounders provide some nice syntheses of current information.

  21. Jeff Morris permalink
    February 14, 2010

    Thanks very much for your comments. I think my comments above in response to Casey fit as well with your input. In recent years the state of the science for applying green chemistry approaches has advanced significantly, and clearly there are opportunities to applying that knowledge to nanotechnology.

  22. Jeff Morris permalink
    February 14, 2010

    Thanks very much for your comments. For additional information on how EPA is approaching gaining a better understanding of nanotechnology and the environment, we have a couple documents on our web site,, that may be of interest to you: the EPA Nanotechnology White Paper (2007) and the EPA Nanomaterials Research Strategy (2009). For information on how EPA is addressing nanomaterials through the Toxic Substances Control Act, see

  23. Al Bannet permalink
    February 16, 2010

    The science fiction horror show portrays a mad scientist who creates a substance that replicates itself exponentially and relentlessly, sort of like the myth of the Sorceror’s Apprentice, but invisable except in its effects. I worry about Murphy’s Law — whatever can go wrong will go wrong.

  24. Diane permalink
    September 28, 2010

    What makes a nanoparticle troublesome? Are goats a threat? I love goat cheese as well :-) I was browsing through your blog and I was checking out some references. I am a co-author of an eBook about panic disorder attacks. Thanks for a great post!

  25. Jeff Morris permalink
    January 12, 2011

    Sorry to be so late in responding to your post. Our research aims to help answer just that question: Is any type of nanoparticle, under certain circumstances, troublesome from an environmental, health, or safety perspective? We don’t start from the presumption that they are troublesome. Rather, we at EPA begin with the understanding that associated with all new technologies are unforeseen consequences, and that asking and addressing forward-looking science questions can better position society to understand, address, and if necessary or possible avoid unintended impacts from the development and use of new processes and materials. This, we believe, will help us all more-fully enjoy the benefits of new technologies by reducing uncertainty over how such technologies might affect the environment.

  26. May 2, 2012

    Goat cheese is my favorite! This was a great post. Thanks for sharing.

  27. permalink
    May 15, 2013

    could possibly copper mineral be used ?

  28. Mobile Office permalink
    October 22, 2013

    Nanotechnology is an amazing yet scary science. Yaks and goats and other livestock have no comparison to the potential danger or possible greatness that this science currently generates.

Leave a Reply

Note: You can use basic XHTML in your comments. Your email address will never be published.

Subscribe to this comment feed via RSS