Gradient EH&S Nano News
Government Report Finds Ineffective Management of Nanomaterial Risks
A recent US EPA Office of the Inspector General (OIG) report concludes that the Agency does not have sufficient information or processes in place to effectively manage the human health and environmental risks of nanomaterials. The December 2011 report details that US EPA has the authority to regulate nanomaterials, but it lacks the requisite data to do so effectively. As described in a previous edition of EH&S Nano News (July 2011), a US EPA-proposed voluntary policy for pesticide manufacturers to identify new products with nanoscale materials was met with minimal industry participation. As a response, US EPA has proposed mandatory reporting rules for nanomaterials under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and it is developing proposed rules under the Toxic Substances Control Act (TSCA). The OIG report noted that US EPA does not have a formal plan for dissemination and use of information gathered under the proposed mandates and criticized the lack of communication to external stakeholders regarding policy changes and the risks of nanomaterials. The report also found that the US EPA proposal to regulate nanomaterials as bulk chemicals faces inherent limitations of the existing chemical-specific statutes coupled with a new challenge of a lack of quantitative risk information on nanomaterials (which is currently based on industry-submitted data). The OIG states that these are significant issues that, left unresolved, will leave US EPA unable to effectively manage nanomaterial risks.
The full report is publicly available here:epa.gov
US EPA Conditionally Registers a New Product Containing Nanosilver
In what may likely be a very controversial move, US EPA announced on December 1, 2011, that it was conditionally registering a pesticide product that contains nanosilver as a "new active ingredient." The product is an antimicrobial pesticide (HeiQ AGS-20) that is used as a preservative for textiles. As a condition of registration, US EPA is requiring additional data on the product to confirm that it will not cause unreasonable adverse effects on human health or to the environment, the general standard for a registration under FIFRA. US EPA received 45 public comments when it announced plans to conditionally register the product on August 13, 2010. The comments, responses, and decision document to conditionally register the product can be found at www.regulations.gov in Docket ID # EPA-HQ-OPP-2009-1012. The final registration is not yet in the docket.
The US EPA press release is available here: epa.gov
The product manufacturer's press release is here: heiq.com
Hot-off-the-Presses: Peer-Reviewed Research Articles of NoteExposure
Dahm, MM; Evans, DE; Schubauer-Berigan, MK; Birch, ME; Fernback, JE. 2011. "Occupational exposure assessment in carbon nanotube and nanofiber primary and secondary manufacturers." Ann Occup Hyg. Dec 8. [Epub ahead of print]
Despite the burgeoning number of current industrial and biomedical applications for carbon nanotubes (CNTs) and carbon nanofibers (CNFs) (e.g., coatings and composites for aerospace, automobiles, and construction; a variety of healthcare applications; electronics; displays; and batteries) and estimates of a 44% increase in the number of employees involved in CNT manufacturing operations between 2006 and 2008, there remains a general lack of published exposure data for workplaces where CNTs and CNFs are manufactured and/or handled. Responding to this data gap, this study reports findings from exposure assessments conducted by the National Institute for Occupational Safety and Health (NIOSH) at six commercial facilities identified as primary or secondary CNT/CNF manufacturers, most of which were small startup companies with pilot-scale operations. The inhalable and respirable mass fractions of elemental carbon (EC) were measured for both full-shift personal breathing zone samples and task-specific area filter-based samples. Transmission electron microscopy (TEM) analysis was also conducted to provide CNT structure count analyses as well as an indication of the structure of the particles collected, including general size, shape, and degree of agglomeration (note that a future paper is to discuss additional data collected using direct-reading instruments that included a condensation particle counter, a photometer, and a diffusion charger). The majority of the exposure sampling from both the primary and secondary manufacturing facilities yielded EC concentrations that were detectable, but below NIOSH's proposed respirable mass-based recommended exposure limit (REL) of 7 μg/m3. Out of 52 samples, there were only two exceedances (7.86 μg/m3 and 7.54 μg/m3) of the proposed 8-hour time-weighted average REL; both exceedances were for inhalable EC samples from secondary manufacturers, which are not directly comparable to the respirable mass-based REL. Overall, the highest EC concentrations and CNT/CNF structure counts were observed at secondary manufacturers during dry power handling processes (e.g., mixing and weighing). Although all were below the proposed REL, the highest EC concentrations and CNT/CNF structure counts from primary manufacturers were observed during the harvesting of raw CNTs after production, including at one facility lacking any engineering controls. Based on a correlation coefficient of 0.44 (p-value = 0.01) for side-by-side samples analyzed for both EC concentration and CNT/CNF structure counts, the investigators concluded that there was good agreement between the mass-based EC metric and microscopic methods. Given that the exposure sampling was conducted for pilot-scale operations, the results indicate that additional exposure assessments are warranted for facilities with full-scale commercial operations.
Toxicity
Mercer, RW; Hubbs, AF; Scabillon, JF; Wang, L; Battelli, LA; Friend, S; Castranova, V; Porter, DW. 2011. "Pulmonary fibrotic response to aspiration of multi-walled carbon nanotubes." Part. Fibre Toxicol. 8:21.
Along with many qualities that are desirable for product, engineering, and medical applications, such as high mechanical stability, carbon nanotubes can also cause undesirable biological effects. Both single-wall carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) elicit inflammatory and fibrotic responses that are qualitatively similar. The aim of this study by Mercer et al. was to evaluate the distribution of MWCNTs to the alveolar interstitium and their potential to cause an interstitial fibrotic response, compared to the distribution and response observed previously with SWCNTs. Mercer et al. observed that, on a mass basis, a much smaller proportion of MWCNTs - approximately 8% - distributed to the alveolar interstitium, compared to approximately 90% observed previously with SWCNTs. The difference in distribution is due primarily to uptake of MWCNTs into alveolar macrophages and the relatively rapid clearance of MWCNTs from the airways. In contrast, previous studies found that very few SWCNTs are taken into alveolar macrophages. Along with the greater distribution of SWCNTs to the alveolar interstitium, SWCNTs also elicited a more pronounced fibrotic response on a mass basis - increasing the thickness of connective tissue from 0.1 μm to 1.1 μm following aspiration of 10 μg of well-dispersed SWCNTs, compared to an increase in thickness from 0.1 μm to 0.2 μm following aspiration of 80 μg of MWCNTs. Although SWCNTs appear to be much more potent than MWCNTs on a mass basis, their potency is comparable based on surface area, which suggests that reactions occurring on the surface of MWCNTs may be important for eliciting the interstitial fibrotic response.
Reports, Reviews, White Papers, and BooksEuropean Commission Defines "Nanomaterial"
The European Commission has recently published a definition of the term "nanomaterial." The definition, as described in the "Commission Recommendations" section of the October 20, 2011, issue of the Official Journal of the European Union, is as follows:
Nanomaterial means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50 % or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm - 100 nm.
In specific cases and where warranted by concerns for the environment, health, safety or competitiveness the number size distribution threshold of 50% may be replaced by a threshold between 1 and 50%.
The Commission will review the definition in 2014, considering new technical and scientific literature.
The proposed definition is publicly available here:eur-lex.europa.eu
Final REACH Implementation Project on Nanomaterials Reports Available
In 2009, the European Commission launched a comprehensive REACH Implementation Project on Nanomaterials (RIPoN) with the aim of providing advice on key aspects of the information requirements, chemical safety assessment, and substance identification components of REACH with regard to nanomaterials. This project has recently generated a series of individual "Task Reports." These reports were subject to review by members of the European Commission Steering Group, comprised of representatives from the European Chemicals Agency (ECHA) and various other stakeholders, including the REACH Competent Authorities Sub-Group on Nanomaterials and experts from industry and non-governmental organizations. The draft Task Reports were opened for comment, discussed at public meetings, revised, re-opened for comment, and then finalized. The final reports will be submitted by the European Commission to ECHA for possible implementation as REACH guidance. Currently, the final Task Reports on information requirements and chemical safety assessment are publicly available. There are several features that distinguish these reports from reports on other types of materials. For example, as compared to more traditional chemicals, the information requirements for nanomaterials will include a reporting requirement for the forms or physical states in which the substance is placed on market or used; and the applicable safety assessments will be required to have been carried out on those particular form(s) and physical state(s). Consensus among experts has yet to be reached on final recommendations related to substance identification.
To view the Task Report on Information Requirements, visit: ec.europa.eu
To view the Task Report on Chemical Safety Assessment, visit: ec.europa.eu
New European Academies Science Advisory Council Report on Nanomaterial Safety
The European Commission's Joint Research Centre and the European Academies Science Advisory Council recently published a report titled "Impact of engineered nanomaterials on health: considerations for benefit-risk assessment." The report summarizes the state-of-the-art knowledge on the safety of engineered nanomaterials, and the results of this independent and scientifically based evaluation suggest that there is limited evidence that nanomaterials present a risk for human health. The report proposes the development of a regulatory framework to reduce the many uncertainties about the potential impact of nanomaterials on health. Many of the proposed recommendations are focused on addressing knowledge gaps related to nanomaterial hazard assessment such as defining dose-response relationships, standardization of toxicological assays, characterization of differences in susceptibility and exposure, and more detailed toxicology studies (e.g., cellular level studies). The authors suggest that, although there are many research projects worldwide assessing these items, there is much concern about their quality and relevance.
To view the complete report, visit:ec.europa.eu Guest Contributor
Should US EPA's Regulatory Reach Encompass Unintentionally Created Nanoscale Materials?
William J. Walsh, Pepper Hamilton LLP
While the question of how best to regulate nanomaterials is rife with controversy (as seems to be the case with many environmental issues these days), this editorial narrowly discusses an emerging debate over whether the US Environmental Protection Agency's (US EPA's) regulatory definition of nanoscale materials should apply only to intentionally created materials. In some cases, traditional manufacturing processes may "unintentionally" create nanoscaled particles. For example, carbon black and titanium dioxide nanomaterials have been created unintentionally for years. There are legal and policy reasons not to regulate unintentionally created nanoscale particles and fibers using the Toxic Substance Control Act (TSCA) premanufacturing notice (PMN) program.
Background
When companies first started developing products using nanotechnology, US EPA did not consider nanomaterials "new chemicals" that would be subject to TSCA's PMN and pesticide registration processes. Obligations under these programs were triggered based on creation of new chemical formulas, not the shapes and sizes of existing chemicals. For example, the nanoscale version of a chemical already on the TSCA Inventory (e.g., carbon or titanium dioxide) would not be listed separately on the TSCA Inventory and would not require a PMN notice. Similarly, US EPA's pesticide office did not require new toxicological tests for nanopesticides.
Since 2005, however, US EPA's TSCA office has reviewed more than 120 new TSCA chemical notices for nanoscale materials, including nanoscale particles and carbon nanotubes (CNT), and taken a number of actions to control and limit exposures to nanoscale materials. As part of its analysis, US EPA's TSCA Office assumes, for purposes of regulating nanoscale materials, that the "rat model [i.e., studies exposing rats to air concentrations of particulates that overload the ability of rat lungs to remove particulates] can identify potential carcinogenic hazards to humans," based on data involving silica, talc, titanium dioxide, PMN 96-175 (lithium manganese oxide), and carbon black. 1 Yet, in the same document, US EPA acknowledges that "no lung cancer hazard is anticipated" in humans because, among other things, chronic active inflammation and cell proliferation do not occur at low doses.2 Similarly, US EPA is concerned for potential pulmonary toxicity, fibrosis, carcinogenicity, mutagenicity, and immunotoxicity based on test data for CNTs and analogous chemicals. 3
On June 17, 2011, US EPA's Office of Pesticide Programs (OPP) proposed to define a ''nanoscale material'' as an"active or inert ingredient and any component parts thereof intentionally produced to have at least one dimension that measures between approximately 1 and 100 nanometers (nm)"4 (emphasis added). During the comment period for this proposal, the International Center for Technology Assessment (an NGO, non-governmental organization) urged US EPA to include "all materials that are produced and which have at least one dimension that measures between approximately 1 and 1000 nanometers" even if they were created inadvertently. The Silver Technology Working Group (an industry effort to collect data on silver nanotechnology and foster good science and public understanding) claimed that including the concept of intentionality in the definition was "profoundly alarming and will lead to substantial confusion and ambiguity."
On the other hand, the Color Paint Pigment Association opposed the US EPA definition because the definition was too broad - virtually all paint pigments are manufactured intentionally. The American Chemistry Council noted that a focus on intentionally manufactured materials is consistent with definitions used by the Executive Office of the President, prior US EPA definitions, the National Institute of Occupational Safety and Health's (NIOSH's) approach, the National Nanotechnology Initiative, Health Canada, the Australia National Industrial Chemicals Notification and Assessment Scheme, and the American Chamber of Commerce comments to the European Union.
To further complicate matters, the European Commission has proposed to define nanomaterials as including "natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm - 100 nm".
The OPP's position that unintentionally produced material is not subject to the applicable regulation is consistent with the long-standing interpretation taken by US EPA's TSCA office. Of course, US EPA's TSCA office is not legally compelled to use the OPP definition. As a practical matter, the final language in the definition may have an inevitable (if not intentional) effect.
The Issues
Careful consideration should be given by regulators before adopting a broad definition of nanomaterials that includes admittedly small particles that are incidentally and unintentionally formed.
First, unlike truly engineered nanoscale particles, unintentionally created small particles are not new and should not be treated as new. Various manufacturing processes inherently create nanosized particles, such as carbon black, titanium dioxide, and other substances. Thus, unless one intentionally develops a new manufacturing technique to create a greater distribution of nanosized particles, there is nothing new to regulate.
Second, health and safety data already exist for these substances, including their nanoscale components. In fact, US EPA is relying on these existing data to justify the regulation of intentionally manufactured nanoscale material. Further, NIOSH developed recommended exposure limits for fine and ultrafine titanium dioxide using existing data, thereby proving that no new regulatory scheme need be applied.
Third, including any unintentionally and even naturally occurring substance that may contain nanoscale particles within the scope of the TSCA regulatory program would greatly increase the administrative burden on US EPA personnel without a clear benefit.
Fourth, innovation and existing uses of common products are likely to be adversely impacted if unintentionally created materials are covered (due to the costs of developing and implementing the tests and the time needed to address regulatory issues).
There are clearly aspects of nanotechnology that should be subject to TSCA regulation. However, as one astute observer noted recently: "despite policy makers repeatedly stating that any form of nanomaterial regulation should be science-based, I have the sense that they are scrambling to use science to justify a predetermined conclusion - that engineered nanomaterials should be regulated on the basis of a hard and fast definition - rather than using science to guide their actions."5
In summary, US EPA continues to regulate nanomaterials. Stakeholders, the Inspector General and Government Accountability Office, among others, urge even more aggressive action.6 The issues being raised concerning the TSCA regulation of unintentionally created nanoscale material should be considered.
1US EPA, TSCA New Chemical Category in Support of a SNUR for One Chemical Substance at 1. EPA Docket: EPA-HQ-OPPT-2009-0686 (October 8, 2009).
2Id. The biology of the human lung differs from that of the rat. It is beyond the scope of the author's expertise to render an opinion on these toxicological issues, which should be commented upon and scientifically determined by technical experts, such as those at Gradient, not lawyers. However, at least some independent groups have concluded that the "hypothesis that the smaller a particle is, the more toxic it is, is not supported by current scientific knowledge." The Institut de recherché Robert-Sauvé en santé et en sécurité du travail (IRSST), Engineered Nanoparticles: Current Knowledge about OHS Risks and Prevention Measures at 68 (Second Edition) (REPORT R-656), available here.
3US EPA, Multi-Walled Carbon Nanotubes and Single-Walled Carbon Nanotubes; Significant New Use Rules, 75 Fed. Reg. at 56,880, 56885 (September 17, 2010) (final rule), available here.
4US EPA, Pesticides; Policies Concerning Products Containing Nanoscale Materials; Opportunity for Public Comment, 76 Fed. Reg. 35,383 (June 17, 2011); EPA-HQ-OPP-2010-0197), available here.
5Define nanomaterials for regulatory purposes? EU JRC says yes, by Andrew Maynard on September 6, 2011, available here.
6US EPA Inspector General, EPA Needs to Regulate Nanomaterial Risks More Effectively (December 29, 2011), available here.