EPA is taking several steps that could result in a stricter approach for addressing nanomaterials than the Bush administration, including crafting new toxics rules in the wake of lackluster results from the last administration’s voluntary stewardship program and reviewing the controversial policy for determining if engineered nanomaterials are subject to regulation under toxics laws.

The agency is also launching a scientific review of how it considers the risks of nanomaterials used in pesticides, which are often used in household products as an antimicrobial agent.

Toxics chief Steve Owens announced the new initiatives during his keynote address at “Trans-Atlantic Regulatory Cooperation: Securing the Promise of Nanotechnologies,” a conference held in London Sept. 10-11 and hosted by Chatham House, the London School of Economics and Political Science, the Environmental Law Institute and the Project on Emerging Nanotechnologies.

Owens’ announcement is prompting optimism among environmentalists, who have long sought to strengthen regulation of the emerging technology, but is prompting concern from industry officials who fear continued uncertainty about the regulatory status of the materials.

Owens focused in particular on the Bush administration’s approach that exempted nanomaterials from review under the Toxic Substances Control Act (TSCA) if the materials are considered to have “the same molecular identity” as bulk chemicals already listed on the agency’s TSCA inventory. But environmentalists have long opposed this approach, arguing that the environmental and health risks posed by nanoscale substances are innately different from bulk chemicals.

In a 2008 agency document, “TSCA Inventory Status of Nanoscale Substances — General Approach,” the agency determined that nanoscale versions of substances that have the same molecular structure of chemicals already appearing on the TSCA inventory are not considered “new” and are not required to go through the new chemicals review process, which can result in imposition of regulatory protections.

According to the 2008 EPA document, a nanoscale material is considered “existing” if the substance has the “same molecular identity as a substance already on the inventory,” while “new” chemicals are chemicals somehow different in chemical structure from the bulk version already listed. “Although a nanoscale substance that has the same molecular identity as a non-nanoscale substance listed on the inventory differs in particle size and may differ in certain physical and/or chemical properties resulting from the difference in particle size, EPA considers the two forms to be the same chemical substance because they have the same molecular identity,” the document states.

But Owens criticized this approach, saying an existing nanomaterial “is subject to much less scrutiny from EPA because of that designation, due to the different ways TSCA treats existing and new chemicals,” according to his prepared remarks.

Despite his criticsms, Owens said officials were not prejudging the outcome of their policy reassessment.“I cannot say what the outcome of that review will be, but I can tell you that we will be taking a fresh look at this issue and at the basis and reasoning for the decision made by EPA last year.”

While he gave few details regarding the review, the move could have far-reaching impacts for industry while bolstering calls from activists for a more precautionary approach to nanomaterials.

A revised policy could have “a lot of different implications” for industry, including how the policy is interpreted and enforced, an industry source says. “What does that mean for nanomaterials in commerce? What does that mean for nanomaterials that have been in commerce for many years?”

The move could mean additional uncertainty for small businesses developing nanomaterials, which are already facing uncertainty about the success of their products, as well as possible enforcement action and new rules under TSCA section 8 and section 4 from EPA, the source says.

Activist groups at the event said they were “optimistic” about the move. A source with the Center for International Environmental Law says the announcement was “quite interesting and encouraging,” adding that they “will have to see how the review process proceeds,” and whether it will be an internal or external review.

Activists have long questioned the EPA approach, pointing out it does not take into account the inherently different properties — and potential risks — of engineered nanomaterials. In a blog post from 2008, Richard Denison, senior scientist at the Environmental Defense Fund, argued that EPA should have declared all nanomaterials to be new chemicals unless they were demonstrated to be the same as their bulk versions.

“EPA’s policy decision flies in the face of nano science, which makes clear that a nanomaterial’s properties are dictated at least as much by its physical characteristics as by its chemical structure,” Denison wrote. “But it gets worse: EPA’s ruling effectively guts the only meaningful opportunity EPA — and hence the public — had to ensure that such nanomaterials get any scrutiny before they hit the market. That’s because EPA has authority to do a pre-market review only for new chemicals.”

Owens also promised to be more aggressive in addressing nanomaterials than the Bush administration’s voluntary Nanoscale Materials Stewardship Program, saying the agency “is taking a more proactive approach toward oversight of nanomaterials to the extent possible under TSCA to fill the data gaps and develop an appropriate regulatory approach.”

For example, EPA is developing a rule slated for 2010 under section 8 of TSCA “to require companies to report a range of information on nanoscale materials, including: data on existing uses, production volumes, specific physical properties, chemical and structural characteristics, methods of manufacture and processing, exposure and release information, and available health and safety data.” EPA is also developing a test rule under section 4 of TSCA requiring “companies to test several manufactured nanomaterials for health and environmental effects.”

Owens also said the agency will be launching a Science Advisory Panel (SAP) review to consider whether the agency is adequately considering the risks surrounding nanomaterials regulated under the Federal Insecticide, Fungicide & Rodenticide Act,which are oftentimes household products utilizing nanosilver as an antimicrobial agent.

“These products raise a number of challenging questions such as what data are needed to evaluate the safety of these pesticides, how should studies on them be performed, and how should EPA assess any potential risks,” Owens said. EPA will “ask these experts for advice of what types of data should be required to assess the risks of nanoscale pesticide ingredients and what our research priorities should be. And we will use this advice to inform our decisions on how to evaluate pesticide products that contain nanoscale ingredients.”

According to a Sept. 16 Federal Register notice, the panel is set to convene Nov. 3-6.