Category: Research

If you are not already familiar with Ron Wernette and his excellent blog, I recommend you add it to your nanolinks at

The blog keeps track of developments and learning opportunities in the field and is a perfect complement to our blog, as the blog’s mission statement demonstrates:

“The Nanotort Law Blog aims to be a useful resource for lawyers and risk managers. It will help you stay abreast of the current state of hazard assessment knowledge, pertinent governmental regulation, industry and NGO standards and guidelines, and other important information germane to environmental, health, and safety risks and potential liabilities. The Nanotort Law Blog will also offer ideas and links to other helpful resources to help you monitor, understand and manage the potential – and as yet unkown – liability risks of Nanotechnologies. “




The President’s Cancer Panel’s Report, referenced in my previous post, makes many important statements about cancer.  One summary statement stands out.  The PCP states:

“Single-gene inherited cancer syndromes are believed to account for less than 5 percent of malignancies in the United States.  An unknown percentage of cancers develop due to normal endogenous [internal] processes [such as aging]. . . . Other cancers develop as a result of exogenous [outside of the body] factors, some of which are controllable.”

Report, Sec. 1, at 1.  The PCP then goes on to point out that the existing studies of the relationship of environmental exposures to cancer are out of date, but that even newer studies cannot take into account the many synergistic effects of multiple exposures in the environment that could lead to cancer.

Part of this problem is due to the complex chain of exposures.  The PCP summarizes the chain as follows:

Use of chemicals or other substances in industry and agriculture:  exposure of workers

Dispersal of  contaminants through:




Consumer products

Entry of the contaminants into the human body through various routes, which may impact both somatic cells and germ cells (egg and sperm)

Occurrence of higher levels of toxic and hormone-disrupting substances in women, including maternal blood, placental tissue, and breast milk

Transference of the substances from the mother to the next generation can occur to the fetus in utero or to a breast-feeding infant

Because the substances may interfere with the genes of the parents, without directly causing disease in the parents, these genes may predispose future generations to cancer.  This transference of the propensity to cause cancer may go from the parents’ genes to the next generation and beyond.

 In one of only a few references to nanotechnology in the Report, the PCP said:  “Limited research to date on unintended health effects of nanomarterials, for example, suggests that unanticipated environmental hazards may emerge from the push for progress.”  Report, Exec. Summary, at iii.

Where does nanotechnology fit into the chain?  At least theoretically, at every stage.  But nanotechnology is a complicating factor in an already complex scientific task.  As a kind of facilitating system – or delivery system, for lack of a more accurate description – nanotechnology may change the characteristics of the substances the technology interfaces with.  This may occur at the earliest stages of developing a use for nanomaterials, but its ultimate impact may not be seen or even measurable for years or generations.  Very little is known about this process.  At the nanolevel, some substances may be absorbed into the human body in unanticipated ways.  Now place this into the exposure chain, and the problems of characterizing and measuring risk increase exponentially.

 I will continue to sort through the Report and its relevance to nanotechnology in future posts.

prod liab imageRecently, the President’s Cancer Panel released its report, “Reducing Environmental Cancer Risk: What We Can Do Now,” which made the bold and distressing statement that “the true burden of environmentally induced cancer has been grossly underestimated.”  Currently, there are approximately 80,000 chemicals on the market in the United States many of which are likely carcinogens that are used by most Americans on a regular basis in their daily lives.  The risks of these carcinogenic substances have a significantly greater impact on children than adults.  The Panel observed that most of these chemicals are “un- or understudied and largely unregulated.”  Among other things, the Panel concluded that research on the environmental causes of cancer has taken a back seat to research on the genetic and molecular mechanisms that cause cancer.  Research into the environmental causes of cancer has been given low priority and insufficient funding, they say.

 What does this report on chemicals and cancer have to do with nanotechnology?  The long-term health risks of nanotechnology are currently unknown.  If, as the Panel states, only a few hundred of those existing 80,000 chemicals have been tested for safety to date, where does that put emerging technologies such as nanotechnology?  Right now, at the bottom of the list.  And if the Panel’s recommendations are implemented, it is likely that available resources will be consumed by studying a fraction of those 80,000 chemicals.

 The Panel identified the following barriers to effective regulation of environmental contaminants:

 “(1) inadequate funding and insufficient staffing,

(2)   fragmented and overlapping authorities coupled with uneven and decentralized enforcement,

(3)   excessive regulatory complexity,

(4)   weak laws and regulations, and

(5)   undue industry influence.”

 It is worth considering the degree to which each one of these barriers to effective regulation may apply to nanotechnology, either now or in the coming months and years.

 Given this state of affairs, what is to be done?  One might reasonably ask:  Why should the public bear the burden of proving that an environmental exposure is harmful?  Would it make more sense to have industry – those developing the substances and placing them on the market – conduct the studies on the human environmental impacts in the first instance?  When it comes to consumer products, it seems that it is only after the fact – after harm has come to persons exposed – that the requisite depth of study is conducted.

 This is an ongoing discussion.  I will be examining other aspects of the Panel’s report in relation to nanotechnology in future posts.

 The report may be found at

In the call for studies on the health and safety of nanoparticles in various uses, it is easy to overlook important questions about what the studies mean.  Does a study demonstrating what may be considered an adverse outcome provide a basis for legal action?  The complex answer is, “Sometimes yes and sometimes no,” or in the words of every law professor, “It depends.”

Let’s take a look a highly publicized study published in late 2009.  See Trouiller et al., Titanium Dioxide Nanoparticles Induce DNA Damage and Genetic Instability In vivo in Mice, CANCER RES. 2009; 69: (22), Nov. 15, 2009.  Researchers from UCLA conducted a study in vivo on mice to test the effects of the titanium dioxide nanoparticles, regularly used in many consumer products, including cosmetics (especially sunblocks), food coloring, toothpaste, and paint.  The researchers herald their study as the first in vivo study to demonstrate a connection between the particular substance and genetic harm.  Previous in vitro studies, they say, produced mixed results and by their very nature did not involve living tissue.

First, a word about how the law views in vitro and in vivo studies.  In vitro studies, such as the Ames test, test the effects of chemicals on bacteria or other cells in a laboratory dish, looking for genetic mutations.  These studies are sometimes offered in a legal setting to suggest that exposure to the substance is carcinogenic in human, on the theory that somatic cell mutations lead to uncontrolled cell reproduction and, ultimately, cancer.  In vivo studies compare laboratory animals exposed to a particular substance to a control group that was not exposed, looking for differences in outcomes between the two groups.  What both types of studies have in common is that they do not involve humans.  As a result, they also have in common the need to extrapolate from the test data to predictable results in humans, a process that is speculative.  In other words, both studies fall short of demonstrating exactly what will happen when humans are exposed to the substance.  But both are relatively fast, inexpensive, and do not involve the ethical dilemmas of testing on humans.

Courts bristle when plaintiffs seek to introduce this kind of evidence, without anything else, in personal injury litigation as proof that exposure to a particular substance caused their illnesses.  The role of courts in determining what evidence is admissible under the rules of evidence is designed to keep frivolous suits from consuming resources and from reaching juries, which might be more impressionable than the court.  Regulators are less constrained than courts, however.  The role of government regulators is circumscribed by the legislation giving them authority.

In the scheme of things, the law prefers in vivo studies to in vitro studies because in vivo studies demonstrate some action of the substance on mammalian living tissue.  But both types of studies are a distant second to epidemiological studies on human populations.  Such statistical studies of risk factors examine groups of humans to determine the strength of relationships between exposures and outcomes.  But even they do not examine the direct impact of the substance on human tissues.

All scientific and statistical studies used to demonstrate carcinogenicity serve to demonstrate the difficulty the law has with understanding and using the studies to make legal decisions.  In the important U.S. Supreme Court case of Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579 (1993), in which the Court provided guidance on determining the reliability of scientific studies in the federal courts (in the context of a toxic torts case involving the prescription drug Bendectin), the Court had the following to say about the distinctions between science and litigation:

[T]here are important differences between the quest for truth in the courtroom and the quest for truth in the laboratory. Scientific conclusions are subject to perpetual revision. Law, on the other hand, must resolve disputes finally and quickly. The scientific project is advanced by broad and wide-ranging consideration of a multitude of hypotheses, for those that are incorrect will eventually be shown to be so, and that in itself is an advance. Conjectures that are probably wrong are of little use, however, in the project of reaching a quick, final, and binding legal judgment – often of great consequence – about a particular set of events in the past.

Id. at 596-97.

There is strength in numbers, however.  The more reliable studies that are conducted showing similar results, the more likely the substance will be regulated effectively.  And the more likely litigants will be able to assemble a package of expert scientific evidence that will support their positions.


An abstract of the article may be found at