EPA Approach to Regulating 

Carbon Nanomaterials

NIST Workshop

March 1, 2011

Zofia Kosim, P.E.

US EPA Office of Pollution Prevention and Toxics 
Office of Pollution Prevention and Toxics

TSCA provides broad authority to:

– Gather information on new and existing 

chemical substances and mixtures

– Require testing of chemicals

– Screen and control unreasonable risks of 

new and existing chemicals

– Coordinate with other Federal agencies

– Maintain TSCA inventory

Toxic Substances Control Act 

(TSCA)
Office of Pollution Prevention and Toxics

New Chemicals Program

Chemicals not on the TSCA Inventory

• Manufacturers or importers of new 

chemicals submit premanufacture 

notices (PMN) [TSCA §5 (a)] 

• Regulation Pending Development of 

Information [TSCA §5(e)]

• Significant New Use Rules (SNUR) 

[TSCA §5 (a) (2)]
Office of Pollution Prevention and Toxics

Carbon Nanomaterials (CNMs) 

Carbon nanomaterials include pure and 

functionalized carbon nanotubes (CNTs), carbon 

nanofibers, and fullerenes.

EPA has received new chemical notices under 

the Toxic Substances Control Act (TSCA) for 

over 100 nanoscale materials and, among them, 

more than 30 for CNMs. 

Production volumes of the CNMs range from kg 

scale to greater than 10,000 kg per year.

 EPA regulates CNMs, usually with Consent 

Orders and Significant New Use Rules.
Office of Pollution Prevention and Toxics

Each CNM or functionalized CNM is considered a 

distinct chemical substance.

Each material has different key parameters. 

EPA recommends using existing EPA test 

methods and OECD’s test methods for 

nanomaterials to measure these parameters. 

Test methods may not be applicable or nonexistent

Carbon Nanomaterials (CNMs)

cont 
Office of Pollution Prevention and Toxics

Carbon Nanomaterials (CNMs)

cont 

Key parameters for fullerenes could include:

 functionalization

 dry particle size distribution

 dustiness

 water solubility

 surface chemistry

Key parameters for CNT could include:

# of walls

inner diameter, outer diameter and length

functionalization

capped or open ended

straight, branched, or tree structure

dry particle size distribution

dustiness
Office of Pollution Prevention and Toxics

Examples of test methods and techniques for 

fullerenes and functionalized fullerenes

• Dry particle size distribution: Scanning 

transmission electron microscopy (STEM ), using a 

dry particle counting method with a resolution of less 

than 1 nanometer and with no counting after 

dispersion in a solution and evaporating solvent on 

the form of the substance which has the highest 

content of particles smaller than 10 microns. 

• Water solubility: OECD 105 test method

• Dustiness: EN 15051 method

• Surface chemistry: Electron energy loss 

spectroscopy (EELS) and/or X-ray photoelectron 

spectroscopy/electron spectroscopy for chemical 

analysis (XPS/ESCA), functionalized probe atomic 

force microscopy (AFM), or Auger electron 

spectroscopy
Office of Pollution Prevention and Toxics

 Challenges

• No nomenclature system has been 

developed for CNTs

• Generally, insufficient data to identify relevant 

properties

• Unclear test methods/relevance of results

• How do chemical-structural and material 

characterization properties correlate with 

physical-chemical properties
Office of Pollution Prevention and Toxics

Addressing Insufficient Data –

Consent Orders

Data may include the size particle distribution, 

certain basic physical –chemical properties, and 

some health studies.

In the Consent Orders, EPA requires some 

health tests (mostly, the 90-day inhalation 

toxicity) and p-chem properties. To protect 

workers, EPA requires NIOSH-approved full 

face respirators with N-100, R-100, or P-100 

cartridges, impervious gloves and full body 

coverage. 
Office of Pollution Prevention and Toxics

Addressing Insufficient Data –

Consent Orders cont.

Due to the lack of data on the CNMs aquatic toxicity and 

environmental fate, the Consent Orders have generally 

required no water releases during manufacturing, 

processing, and use of CNMs. 

No established methods to determine the concentration 

of the CNMs in water 

EPA has allowed very limited releases of CNMs for 

surface water in one case where the manufacturer 

provided test data.
Office of Pollution Prevention and Toxics

 Environmental Fate and Exposure

• The Agency does not have models or methods designed to predict 

the fate of, or exposure to, CNMs in the environment.

• Combined with the lack of test results for nanomaterials, there is 

uncertainty in estimating removal efficiencies, degradation halflives, partitioning, and transport of nanomaterials. 

• To address this uncertainty, EPA uses a bounding, “what-if” 

scenario that assumes CNMs are released into the environment, 

are persistent, bioaccumulate, and are highly mobile until a 

submitter demonstrates otherwise. 

 Guideline posted on EPA public website

http://www.epa.gov/oppt/exposure/pubs/guidance.htm
Office of Pollution Prevention and Toxics

 Environmental Exposure

Screening level estimates used to determine if 

manufacture, processing, or use of nanomaterials result 

in releases sufficient to warrant control 

Two exposure scenarios for nanomaterials: 

 One simulates releases to water (0% wastewater treatment 

removal) 

 Second simulates releases from sludge (100% adsorption to 

wastewater treatment sludge followed by 100% desorption from 

sludge to groundwater)

Purpose of these scenarios is to create bounding 

estimates for maximum concentrations
Office of Pollution Prevention and Toxics

 Ecotoxicology

No established concern concentration for CNMs: 

• toxicity of e.g., CNTs generally reported in the 10s to 100s ppm for 

both water and sediment borne material 

• Sublethal effects of CNTs have been noted in fish as low as 100 ppb.

• The solubility of CNTs is predicted < 1 ppb, but stable dispersions 

 may be created in the presence of natural organic matter or via

 functionalization (which is environmentally feasible).

• Uptake studies in whole aquatic organisms indicate that CNTs do not

 cross the gut lumen suggesting uptake is limited to ingested material.

• The broad range of potential CNT forms that may affect 

 ecotoxicology: functionalization; length and end-capping; presence

 of catalyst metals; level of purity
Office of Pollution Prevention and Toxics

Environmental Risk Assessment

an example for CNTs

• Based on the framework for other new chemicals, EPA 

models predict no ecological effects at saturation of 

CNTs in water which would generally lead EPA to 

conclude low environmental hazard and risk for CNTs, 

as manufactured.

• However, due to the transformation potential of CNTs 

and uncertainty of the relevance of existing data, EPA 

considers the ecological hazard and risk of CNTs to be 

inconclusive. 

• Generation of additional data would be required if a 

company wanted to release CNTs to the environment.
Office of Pollution Prevention and Toxics

 Occupational Exposures –

 Challenges

• Do large agglomerates break down into respirable and

 inhalable particles that can reach the deep lung?

• No metric to describe the propensity to break down

• How do CNMs disperse in lung/other biological fluids? 

• Occupational inhalation exposures to respirable

particles are a key concern

• No consensus approach

• Highly dependent on model and assumptions

• Unclear how to interpret/utilize experimental data
Office of Pollution Prevention and Toxics

Occupational Exposures -

 Challenges

• Validated exposure monitoring data

• Early studies focused on identifying and reducing 

 emission hotspots in facilities, 

• did not quantify worker exposures

• may represent worst case exposure scenarios,

• but did not identify which particle forms

• What percentage of particle detections are of actual 

CNMs rather than soot or organic carbon?

• What are the characteristics of the actual CNMs from 

such exposures compared to the CNMs as 

manufactured or generated for a toxicity study
Office of Pollution Prevention and Toxics

Human Health - Consumer 

Exposure

• The following forms of CNMs may be 

distributed to consumers:

– completely reacted (cured); 

– incorporated or embedded into a polymer 

matrix that itself has been completely 

reacted (cured); 

– embedded in a permanent solid polymer 

form that is not intended to undergo further 

processing except for mechanical 

processing;
Office of Pollution Prevention and Toxics

Consumer/General Exposure -

Challenges

• Are CNMs chemically bound in composites or 

just embedded? How stable are the CNMs in 

the composites? What is the material 

lifecycle?

– Some consent orders may require testing to help 

address this issue. 

• Thermogravimetric analysis suggests raw 

CNTs will be easily incinerated.

• What about under actual incineration and 

composite conditions?
Office of Pollution Prevention and Toxics

Human Health Risk Assessment

• A typical assessment for other new chemicals 

would establish an exposure limit based on 

the best available analogue to estimate 

potential risk. 

• Due to the uncertainty of the relevance of 

both hazard and exposure data. EPA 

considers the human health hazard and risk 

of CNMs to be inconclusive. 

• Generation of additional data would be 

required if a company wanted to manufacture 

CNMs without the current restrictions found in 

consent orders. 
Office of Pollution Prevention and Toxics

 Regulatory Management of CNMs

EPA needs:

•Identification of parameters to 

 measure

• Measurement methods

• Testing protocols 

• Valid data
 Contact Information

http://www.epa.gov/oppt/nano/

 www.regulations.gov

epa-hq-oppt-2004-0122

kosim.zofia@epa.gov 

 202 564-8733