Silver Nanoparticles: NIOSH Seeks Information and Comment

Today's Federal Register carries a notice from the National Institute for Occupational Health and Safety (NIOSH) requesting information and comments regarding silver nanoparticles. NIOSH

has initiated an evaluation of the scientific data on silver nanoparticles
(AgNPs) to ascertain the potential health risks to workers and to
identify gaps in knowledge so that appropriate laboratory and field
research studies can be conducted. . . .

. . . gathering data to determine whether a
health risk to workers may exist from exposure to AgNPs and if specific
risk management guidance is needed to prevent exposure. . . .

Information is particularly needed for determining the relevance
of bile duct hyperplasia and hepatocellular necrosis observed in AgNP
exposed rats, as well as information on: (1) Sources of AgNP exposure,
(2) factors that influence worker's exposure, (3) in-place exposure
control measures (e.g., engineering controls) and work practices that
are effective in reducing worker exposures, and (4) appropriate
measurement methods and exposure metrics for characterizing workplace
exposures. . . .

Examples of requested
information include the following:
    (1) Identification of industries or occupations in which exposures
to AgNPs may occur.
    (2) Trends in the production and use of AgNPs.
    (3) Description of work tasks and scenarios with a potential for
exposure to AgNPs.
    (4) Workplace exposure measurement data in various types of
industries and jobs.
    (5) Case reports or other health information demonstrating
potential health effects in workers exposed to AgNPs.
    (6) Research findings from in vitro and in vivo toxicity studies,
including physical-chemical characterization of AgNPs.
    (7) Information on control measures (e.g., engineering controls,
work practices, PPE) being taken to minimize worker exposure to AgNPs.
    (8) Information on measurement methods and exposure metrics that
can be used to quantify worker exposure to AgNPs including information
on the limitations of those methods in quantifying exposures?


Information submitted my include "published and unpublished reports and research findings".

"All information received in response to this notice must include the agency name and docket number (CDC-2012-0014; NIOSH-260)".  and may be submitted either online via - instructions on how to submit are available on the website - or by mail to 

NIOSH Docket Office,

Robert A. Taft Laboratories,

4676 Columbia Parkway, Cincinnati, OH 45226.


Comments and information submitted will be posted to the docket on The deadline for submitting either comments or information is February 19, 2013.

NIOSH has compiled a listing of relevant publications regarding AgNPS, "Evaluation of the Scientific Data on Silver Nanoparticles (AgNPS)" and will be posting that listing to the docket on Several studies of silver nanoparticles are listed as references in the notice and presumable compose the bulk of the listing. This posting will be updated when the list is available.

For further information please contact

Ralph Zumwalde, NIOSH,


Robert  A. Taft Laboratories,

4676 Columbia Parkway, Cincinnati, Ohio 45226,
telephone (513) 533-8320

or Eileen Kuempel, telephone (513) 533-8363


"Evaluation of the Scientific Data on Silver Nanoparticles (AgNPS)" has been posted to the docket on

NIOSH Recommends Exposure Limit of 7 μg/m 3 for Carbon Nanotubes

This article originally appeared on the National Nanomanufacturing Network's InterNano website. It is licensed under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported.

In late November, the National Institute for Occupational Safety and Health (NIOSH) published a Current Intelligence Bulletin entitled "Occupational Exposure to Carbon Nanotubes and Nanofibers." The document is not an official "agency determination or policy," and was released solely by NIOSH for peer-review and comment. NIOSH's carbon nanotube recommended exposure limit (CNT REL) is set at 7 μg/m 3 for these preliminary purposes.

The old saying that "a picture is worth a thousand words" is once again proved by the document's cover image which is a remarkable "field emission micrograph of a multi-walled carbon nanotube…penetrating the pleura of the lung." The finely detailed image of a CNT penetrating a lung membrane should cause any reader to stop and closely consider the document's recommendations.

The document begins by noting that while there are no scientific reports of "adverse health effects in workers producing or using carbon nanotubes…or carbon nanofibers," NIOSH is concerned because some studies have shown that the potential for worker exposure exists. Additionally, some in vivo studies have shown adverse reactions to carbon nanotubes in rodents -- including pulmonary inflammation and fibrosis. Further, some in vitro and in vivo studies have led researchers to theorize that inhalation of certain carbon nanotubes in large doses may potentially cause asbestos-type exposure effects.

NIOSH explains that the scientific basis for its CNT REL is an extrapolation from subchronic in vivo toxicity studies in rodents. "The REL is based on the available subchronic and short-term animal dose-response data of early-stage fibrotic and inflammatory lung response to CNT exposure. Benchmark dose (BMD) estimates from the animal data (and the 95% lower confidence limit estimates of the BMD) have been extrapolated to humans by accounting for species differences in alveolar lung surface area. Working lifetime exposure concentration have been calculated based on estimates of either the deposited or retained alveolar lung dose of CNT assuming an 8-hour time-weighted average (TWA) work shift exposure during a 40-hour work week, 50 weeks per year, for 45 years."

However, because a risk of adverse lung effects may occur even below the 7 μg/m 3 CNT REL, NIOSH further recommends reducing airborne levels of nanoscale carbon to as low as possible. Additionally, NIOSH recognizes that the REL is based on a mass dose metric which might not be appropriate for nanoscale materials because "a mass-based sampling method may not be sufficiently sensitive to detect all [carbon nanotubes] and [carbon nanofiber] structures in the air at low mass concentrations." Accordingly, NIOSH recommends additional research to determine the most appropriate dose metric.

The CNT REL is not provided in isolation, NIOSH also recommends that employers and workers follow the detailed workplace safety measures outlined in its comprehensive guidance document, "Approaches to Safe Nanotechnology: Managing the Health and Safety Concerns Associated with Engineered Nanomaterials." To this end, NIOSH provides summary information outlining the basic measures explained in its "Approaches" document.

Another notable feature of the document is its position regarding worker medical screening and surveillance. NIOSH concludes "that workers occupationally exposed to [carbon nanotubes] and [carbon nanofiber] may be at risk of adverse respiratory effects. These workers may benefit from inclusion in a medical screening program recommended as a prudent means to help protect their health." This last quasi-recommendation alters NIOSH's prior position that "[t]he current body of evidence about the possible health risks of occupational exposure to engineered nanoparticles is quite small. Insufficient scientific and medical evidence now exists to recommend the specific medical screening of workers potentially exposed to engineered nanoparticles."

The document closes by listing 15 scientific research needs to "assist NIOSH in evaluating the occupational safety and health concerns of working with [carbon nanotubes] and [carbon nanofiber]."

Finally, for those keeping track, in 2005, NIOSH proposed a REL for ultrafine TiO2 (essentially nanoscale TiO2) of .1 μg/m 3. Bayer Material Sciences previously set a worker exposure limit for its multi-walled carbon nanotube products (BayTubes) at .05 mg/m 3 in 2009. Similarly, NIOSH's REL for carbon black is 3.5 mg/m 3, and OSHA's permissible exposure limit for respirable synthetic graphite is 5 mg/m 3.


National Institute for Occupational Safety and Health, Current Intelligence Bulletin, "Occupational Exposure to Carbon Nanotubes and Nanofibers," p. 3, available at (last visited Dec. 9, 2010).

National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Department of Health and Human Services, Approaches to Safe Nanotechnology: Managing the Health and Safety Concerns Associated with Engineered Nanomaterials (2009) available at

New Edition of Nanotechnology Law Report

Here is the Summer 2009 edition of Nanotechnology Law Report.  The newsletter contains the below-listed articles (and more):

  • EPA Issues Significant New Use Rules for Carbon Nanotubes
  • Are Nanoparticles Released by Cutting or Compounding Nano-Composites?
  • Annual Nano TiO2 Production Estimated at 44,000 Metric Tons
  • Are Nano Consumer Products Headed Underground?
  • Oversight of Next Generation Nanotechnology
  • Regulating Nanotechnologies
  • More Interesting Nano-Regulatory Developments
  • Nano Tug of War
  • Pumpkins & Nanoparticles
  • Green Nano
  • NanoBiotech 2009
  • Take two silver nanoparticles and call me in the morning
  • International Approaches to the Regulatory Governance of Nanotechnology
  • ETUC Resolution on Nanotechnologies and Nanomaterials
  • Private Spending on Nano Exceeds Government Spending
  • EMERGNANO Released

Nano Insurance Conference

Chubb Insurance is hosting a one-day nanotechnology insurance conference on October 13, 2009 in North Branch, New Jersey:

"Nanotechnology: What is the Best Safety and Risk Management Approach?" 

From the conference website:

"This conference brings together prominent nanotechnology speakers who will review nanotechnology background, health and safety, and potential insurance and liability issues. Current risk assessment and 'best practice' controls will be shared, helping attendees better recognize and manage potential nanotechnology risks. A nanotechnology toolkit will be provided to help attendees stay abreast of critical developments in this dynamic field."

Speakers include: Charles Geraci (NIOSH), Charles Kingdollar (General Reinsurance Corp.); John Monica (Porter Wright); Susan Berry (DRS Technologies); Ganesh Skandan (NEI Corp.); William Barr (Chubb); Erik Olsen (Chubb); and Louise Vallee (Chubb).

More from the conference website:

Emerging risks require new risk management practices. Nanotechnology applications have outpaced safety and health research. The big challenge is trying to figure out a risk management roadmap when there is a scientific and regulatory abyss with the potential for future litigation looming in the distance. Companies that delay nanotechnology innovation awaiting safety consensus or regulations risk falling behind the competition. While these tiny materials and processes are big business, many risk managers and insurance buyers haven’t fully considered potential risks to employees, consumers and the environment, resulting in workers compensation, product liability and environmental liability exposures. Company risk managers and insurance buyers would value and benefit from knowledgeable broker and agent guidance. Application and control strategies considered now may have far-reaching future implications.

Nano insurance issues have received a lot of renewed interest lately.  This should be a great conference on the topic and is open to the public.  Hope to see you there.

Nanotechnology Law Report -- Spring 2009

NIOSH Guidance on Workplace Exposure

The National Institute of Occupational Safety and Health (NIOSH) has just today released in "Interim Guidance for the Medical Screening of Workers Potentially Exposed to Engineered Nanoparticles."  Before now, NIOSH was keeping mostly quiet on the issue of nanoparticles, and this report gives some insight into the agency's consideration of the issues.

You may remember that NIOSH last made news concerning nanotechnology when it publicly disagreed with EPA's determination to not treat nanoparticles as "new" chemicals under the Toxic Substances Control Act based on size only.  A review of that item appears here.

Today, NIOSH released its 35-page Current Intelligence Bulletin, and is also seeking comments concerning recommendations on exposure registries for nanoparticles.  However, like other agencies, NIOSH determined that there is not enough data to proceed to full regulation.  The Bulletin states, "Although increasing evidence indicates that exposure to some engineered nanoparticles can cause adverse health effects in laboratory animals, no studies of workers exposed to the few engineered nanoparticles tested in animals have been published.  The current body of evidence about the possible health risks of occupational exposure to engineered nanoparticles is quite small.  Insufficient scientific and medical evidence now exists to recommend the specific medical screening of workers potentially exposed to engineered nanoparticles." (emphasis original).  NIOSH even provides information on the limited data in Appendix D of the Bulletin.  However, the report is quick to point out that employers should not be precluded from considering "taking precautions beyond standard industrial hygiene measures."

The Bulletin provides insight into NIOSH's thoughts about nanotechnology, including its definition of nanotechnology, which had previously been mostly unknown.  Because NIOSH admits to the shortcomings in the available data and information, it is expected that more will be forthcoming from the agency.  In the meantime, however, NIOSH makes some simple recommendations for nanoparticle protection, including controlling exposure to nanoparticles, conducting hazard surveillance for implementing controls, and establishing medical surveillance to evaluate the effectiveness of any controls.

NIOSH Urges EPA to Treat All Nanoscale Materials as New Chemical Substances Under TSCA

New chemical substances that are not on EPA's existing Toxic Substances Control Act (TSCA)chemical inventory are subject to premanufacturing notice and approval requirements.  Many NGOs have urged EPA to treat all nanoscale materials as new chemical substances under TSCA because of potential environmental, health, and safety concerns shown in laboratory settings.  Such treatment would trigger TSCA's premanufacturing notice and approval requirements.  This past July, EPA indicated it did not currently intend to accept this approach because it considers "new" chemicals as those that have molecular identities that are not reflected on the inventory.


On September 7, the National Institute of Occupational Health and Safety (NIOSH) submitted written comments on EPA's new Nanoscale Materials Stewardship Program in which it urged EPA to change its position and treat all nanoscale materials as new chemical substances under TSCA. In support of its position, NIOSH suggested that "EPA consider particle size . . . in its decision criteria for determining if a nanoscale material is considered a new chemical for the TSCA Inventory. Reducing the particle size to the nanoscale can result in unique or enhanced properties of the nanoscale substance, which can also alter or increase the biological activity and potential toxicity. Thus, the hazard potential of a nanoscale form of a substance may differ substantially (qualitatively and/or quantitatively) from the parent/bulk material that may be listed on the Inventory."
This sets up a possible showdown between EPA and NIOSH on the future treatment of nanomaterials under TSCA. Stay tuned.

NIOSH Guidance For Nanotechnology Employers

By, Jaime T. Landrum:

As the impact of nanotechnology grows, more companies are considering the utilization of nanotech products and processes in the workplace. Questions regarding nanotechnology's effect on the American worker, however, come side-by-side with these business decisions. As reported at Occupational Hazards, The National Institute for Occupational Safety and Health (NIOSH) is expected to issue guidance for employers facing these problems.

Doug Trout, Associate Director for Science for the Division of Surveillance, Hazard Evaluations and Field Studies discussed this issue at the International Conference on Nanotechnology Occupational and Environmental Health and Safety last week. According to the article, NIOSH will recommend that all nanotechnology employers implement an occupational health surveillance program designed to help employers evaluate the risks and necessary protections resulting from nanotechnology's use. The necessity for such guidance is apparent, considering "the growth of nanotechnology in the workplace, the unique physical and chemical properties of nanomaterials and early evidence suggesting that 'nanoparticles may have toxic effects greater than larger-size particles and at lower doses.'"

For those unaccustomed to the field of occupational health, the article explains that an occupational health surveillance program includes hazard surveillance and/or medical surveillance. These two components are designed to identify and monitor workplace hazards and occupational health problems.

The first step in any health surveillance program is a needs assessment. NIOSH intends to provide a needs assessment framework for employers, including recommendations for the evaluation of various risk factors. We know, however, that the needs assessment will contain a hazard assessment and an exposure assessment. The article quotes Trout as stating "The purpose of this needs assessment in an occupational setting is to determine – by performing hazard and exposure assessments – whether a health risk due to occupational exposure [to nanomaterials] exists in the workplace."

As most employers already realize, the research on the risks and effects of nanotechnology is still evolving. Trout is quoted as acknowledging that "information may not be available to make a well-informed determination of risk." For that reason, "periodic reassessment" will be of vital importance in the workplace.

Even NIOSH cannot provide definitive answers to nanotechnology employers- at least not yet. Everyone agrees, however, that the use of nanotechnology may pose a significant risk to employees. The NIOSH guidance will provide some welcome relief to employers struggling to understand what the dangers of nanotechnology are and how to avoid them.

For the full article, see here.

NIOSH to Test Certified Respirators

The National Institute of Occupational Health and Saftety's (NIOSH)National Personal Protective Technology Laboratory (NPPTL) at NIOSH recently announced it intent to test currently certified repirators to determine whether they protect wearers against nanoparticle inhalation.  The NIOSH testing follows up on a University of Minnesota study pointing to the effecacy electrostatically charged filters in screening out nano-sized particles.  NPPTL also intends to conduct tests to determine whether nanoparticles will penetrate approved personal protective clothing.  Along with its announcement, NPPTL also noted that there are currently no specific exposure limits for nanoparticles, and that the decision to wear repirators is left to professional judgment. 

Inside OSHA, November 13, 2006, Vol. 13 No.23.