EPA Consent Order for Multi-Walled Carbon Nanotubes
Last month we reported on a press release by Thomas Swan & Co. Ltd. of the United Kingdom indicating the company had recently entered into a PMN consent order with the EPA under the Toxic Substances Control Act (“TSCA”) concerning one of its multi-walled carbon nanotube (MWCNT) products. Barring an unusual coincidence, it appears that EPA has recently published a redacted version of the Swan Consent order here.
The order makes it clear that the PMN was submitted pursuant to § 5(a)(1) of TSCA, and that it covers a MWCNT product. Additionally, the consent order places several requirements on the manufacturer. Specifically, the manufacturer is required to:
- Deliver 1 gram of the MWCNTs to EPA with a copy of MSDS for the product;
- Conduct “90 day inhalation toxicity study in rats with a post exposure; observation period of up to 3 months, including bronchoalveolar lavage fluid (“BALF”) analysis (OPPTS 870.3465 or OECD 413);
- Submit material characterization data within six months (see below);
- Ensure employees “use gloves impervious to nanoscale particles and chemical protective clothing;” and
- Ensure employees “use a NIOSH-approved full-face respirator with an N-100 cartridge while exposed by inhalation in the work area.”
Regarding the second requirement, the consent order also provides the manufacturer with an opportunity to submit toxicity testing data under the Agency’s new Nanoscale Material Stewardship Program as an alternative to the 90 day mouse inhalation test: “If, for example, a consortium of companies commit to testing a representative set of MWCNT for subchronic mammalian toxicity, EPA may consider waiving the triggered testing requirement. EPA would be willing to facilitate the process in coordination with other ongoing health effects testing for MWCNT nationally and internationally. EPA would consider accepting the results of such testing in lieu of triggered testing in this order.”
Regarding material characterization information, EPA is requiring the manufacturer to submit the following within six months:
- Type of multi-walled carbon nanotube (concentric cylinders or scrolled tubes; number of walls/tubes);
- Configuration of nanotube ends (e.g., open, capped);
- Description of any branching;
- Width/diameter of inner most wall/tube (average and range);
- Carbon unit cell ring size and connectivity;
- Alignment of nanotube along long axis (straight, bent, buckled);
- Hexagonal array orientation used in the manufacture of the nanotube;
- Particle size of catalyst used in the manufacture of the nanotube;
- Molecular weight (average and range); and
- Particle properties: shape, size (average and distribution), weight (average and distribution), count, surface area (average and distribution), surface to volume ratio, aggregation/agglomeration.
Finally, manufacturers of MWCNTs (other than Thomas Swan) will be interested in two of EPA’s general legal conclusions expressed in the consent order:
“EPA is unable to determine the potential for human health effects from exposure to the PMN substance. EPA therefore concludes, pursuant to § 5(e)(1)(A)(i) of TSCA, that the information available to the Agency is insufficient to permit a reasoned evaluation of the human health effects of the PMN substance.”
“In light of the potential risk to human health posed by the uncontrolled manufacture, import, processing, distribution in commerce, use, and disposal of the PMN substance, EPA has concluded, pursuant to § 5(e)(1)(A)(ii)(I) of TSCA, that uncontrolled manufacture, import, processing, distribution in commerce, use, and disposal of the PMN substance may present an unreasonable risk of injury to human health.”
No doubt other MWCNT manufacturers will feel the need to file PMN’s for their products similar to Thomas Swan given the language of the consent order.
