CDTSC and EPA Hold Public Workshop on State and Federal Nanomaterial Activities

On September 22, 2010, the California Department of Toxic Substances Control (CDTSC) and the U.S. Environmental Protection Agency (EPA) held a public workshop on state and federal nanomaterial activities. During the workshop, CDTSC and EPA discussed the results of California’s data call-in (DCI) for carbon nanotubes (CNT), its plans for future DCIs, and EPA’s efforts related to CNTs. More information, including the meeting presentations, is available online.

The candidate chemicals for CDTSC’s second DCI, which it intends to issue this Fall, include nanosilver, nano zero valent iron, nano titanium dioxide, nano zinc oxide, nano cerium oxide, and quantum dots. CDTSC may also include in the DCI a request for more information concerning CNTs incorporated in nanometals. According to CDTSC, the DCI will focus its initial questions on analytical test methods for the respective nanomaterial chemical, as well as its metabolites and breakdown products, in various matrices. The meeting presentations for each of the DCI candidates include more specific information regarding applications, production, human health and environmental concerns, why CDTSC is interested, and possible DCI questions.

Jim Alwood, EPA Chemical Control Division, gave two presentations: “Assessing and Managing Risks of CNTs under TSCA — Representative Case Studies,” and “Nanotechnology Regulation at EPA.” In the first presentation, Alwood reviewed EPA’s September 17, 2010, final significant new use rules (SNUR) for multi- and single-walled CNTs that were the subject of premanufacture notices (PMN). According to Alwood, under the Toxic Substances Control Act (TSCA), EPA has received new chemical notices on over 100 nanoscale materials, and over 30 CNTs and fibers. At this time, EPA does not have models or methods to predict the fate of, or exposure to, CNTs in the environment, and there is uncertainty in estimating removal efficiencies, degradation half-lives, partitioning, and transport of nanomaterials. To address this uncertainty, EPA uses a bounding, “what if” scenario, which assumes CNTs are released into the environment, are persistent, bioaccumulate, and are highly mobile until a submitter demonstrates otherwise. EPA uses two exposure scenarios for nanomaterials: one simulates releases to water (zero percent wastewater treatment removal), and the second simulates releases from sludge (100 percent adsorption to wastewater treatment sludge followed by 100 percent desorption from sludge to groundwater). According to Alwood, EPA would require the generation of additional data if a company wanted to release CNTs to the environment. Occupational exposure challenges include the lack of a metric to describe the propensity of CNTs to break down; uncertainty how CNTs disperse in lung or other biological fluids; and that occupational inhalation exposures to respirable particles are a key concern. Regarding consumer and general exposure challenges, issues include whether CNTs are chemically bound in composites or just embedded, and whether CNTs are easily incinerated under actual incineration and composite conditions. For human health risk assessment purposes, due to the uncertainty of the relevance of both hazard and exposure data, EPA considers the human health hazard and risk of CNTs to be inconclusive. EPA would require the generation of additional data if a company wanted to manufacture CNTs without the current restrictions found in consent orders.

Alwood’s second presentation included an overview of how EPA is regulating nanomaterials. In addition to SNURs, EPA intends to promulgate a TSCA Section 4 test rule for certain nanoscale materials, and TSCA Section 8(a) (reporting of available use, production volume, exposure, and toxicity data for existing nanoscale materials) and 8(e) (notices of substantial risk) rules. According to Alwood, “numerous” PMNs have completed the 90-day review period, and EPA has implemented requirements to prevent human and environmental exposure; requirements to develop data; consent orders; and SNURs. Alwood noted that EPA’s Office of Pesticide Programs (OPP) is reviewing how to regulate active and inert ingredients that are nanoscale materials, and the data that would be required. OPP has prepared a draft policy requiring the submission of an “adverse effects” notification under Section 6(a)(2) of the Federal Insecticide, Fungicide, and Rodenticide Act if a registrant has information regarding the presence of a nanoscale material in a pesticide product. The draft revised guidance is now being reviewed by the Office of Management and Budget. The Office of Air is examining nanomaterial fuel additives, such as cerium oxide.

Both CDTSC and EPA repeatedly expressed their interest in talking to and meeting with stakeholders. Both CDSTC and EPA have been less successful in obtaining data concerning nanomaterials than they would have liked; CDTSC through its CNT DCI, and EPA through its Nanoscale Material Stewardship Program. Given the lack of clarity regarding the treatment of confidential business information, and concern over how CDTSC or EPA would use their data, companies were less than eager to provide information. As a result, CDTSC and EPA appear to be working together more closely. According to CDTSC, effective June 1, 2010, it entered into a memorandum of understanding (MOU) with EPA concerning nanosilver. Just last month, CDTSC announced on its website that it is drafting a broader MOU with EPA “to facilitate information exchange, collaboration and outline a working partnership between the agencies on emerging chemicals, green chemistry and materials management.” More information regarding the MOUs is available online.