Engineered nanoparticles, or particles that are intentionally engineered at the atomic and molecular scale to exhibit novel properties, have tremendous potential to foster innovation. The possibilities are endless, in part because of the versatility in form; nanoparticles can be suspended in liquids, can be airborne, and can be structured into a film. But these innovative opportunities are not without risks. Some non-biodegradable nanoparticles may endanger health because they can be transported to places in the human body in new ways, such as across the blood, brain or placental barriers.
Regulators need a profound level of knowledge in order to set threshold values that define tolerable risks, which is currently unavailable for nanoparticles. In the absence of information surrounding nanoparticles, the U.S. and the European Union (EU) have different approaches. The EU takes precautionary action when chemicals pose possible threats to human health and the environment. In the U.S. the actual risk must be demonstrated before taking precautionary and preventive action.
One use of nanoparticles is in nanosilver, which has powerful antibacterial properties and can be applied to wounds in innovative ways. For example, including nanosilver in hospital dressings can often prevent infection without the use of antibiotics. However, most experts agree that introducing powerful antimicrobial nanoparticles like nanosilver into common household products is unnecessary and may pose a risk to health. The toxicity of nanoparticles is different than in its bulk form: while the toxicity of silver in its normal state is generally considered to be relatively low, there is some concern that nanosilver may be promoting bacterial resistance and is related to the increased incidence of allergies. Nanosilver is believed to be the most highly utilized nanoparticle in production, and is added to personal-care products, textiles, kitchenware and appliances.
While the potential exposure to nanoparticles is increasing along with the number of products that contain nanoparticles, the knowledge to provide proper foundation for human risk assessment is unavailable. Increasing concentrations of nanomaterials in groundwater and soil may present the most significant exposure. The U.S. regulates some nanoparticles through the Toxic Substances Control Act (TSCA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). For example, the Environmental Protection Agency (EPA) assigned silver a Chemical Abstract Service (CAS) number which does not speak to the size of the silver approved. Thus, nanosilver is technically already an approved chemical that does not trigger regulatory oversight. Nevertheless, the EPA gave approval to a Swiss company for the use of nanosilver under a separate conditional registration as a preservative pesticide in textiles, which means that their products are allowed to enter the market while research on reproductive and development toxicity is being done. The EPA also approved other registrations of silver without knowledge that these products also contained nanosilver. The EPA is continuing to assess the risks of some nanoparticles, and the California Department of Toxic Substances Control is also exercising its authority under its Health and Safety Code to request information on environmental and health impacts from six nanoparticles, including nanosilver.
While the current U.S. system puts the burden of proof on the EPA to show harm, the European Union is following the precautionary principle to place the burden of proof on manufacturers, importers and producers. The Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) Regulation will be fully implemented in 2018 for all new and existing chemicals, including nanoparticles. While REACH has some limitations, for example only nanoparticles manufactured or imported over one ton are included in the law, the regulation may influence the production of nanoparticles in the U.S. made for export and perhaps lead to an increase in disclosure on the health risks of nanoparticles such as nanosilver.
As the types of nanoparticles increase, the potential for unintended health consequences will also increase. Policymakers are considering how human populations may be exposed to engineered nanoparticles in order to create regulations that foster innovation and manage the potential risks to human health. And before products introduced into the stream of commerce, scientists and engineers are being called upon to provide proactive research to assess the risks of nanoparticles and clearly delineate the benefits to society.
This blog post was developed by Monica Hammer, J.D., Visiting Attorney Fellow at the Network for Public Health Law – Mid-States Region at the University of Michigan School of Public Health.
The Network for Public Health Law provides information and technical assistance on issues related to public health. The legal information and assistance provided in this document does not constitute legal advice or legal representation. For legal advice, readers should consult a lawyer in their state. The views expressed in this blog do not represent those of the Robert Wood Johnson Foundation.