Among the grants being funded:
A study of the absorption and toxicity of nanoparticles on skin. (Several cosmetic products already contain nanoparticles.)
A study of what happens to nanoparticles when they get into drinking water, how they interact with other pollutants there, and how toxic they are in water.
An ant carries a 1-millimeter chip made with nanotechnology at England's University of Huddersfield.
Studies of nanoparticles' effects on cultured human lung tissues and in the airways of live animals -- including a test of whether nanoparticles cause especially severe inflammation, as some suspect.
Studies of the environmental impacts of nanotubes that have settled into marine and freshwater sediments, and the effects of nanoparticles on aquatic bacteria, algae and plankton.
A study of the conditions under which nanoparticles may absorb -- and perhaps later release -- environmental contaminants.
Scott Walsh, a project manager at Washington-based Environmental Defense, called the EPA grants "a great start" but decried the federal government's failure to invest more in the effort.
"Government is not yet investing enough to ensure that the risks are discovered in the laboratory instead of in our bodies, our back yards and our workplaces," Walsh said. "We're probably $90 million shy of what we need to be spending to do the job right."
The EPA is not the only federal agency looking into the safety of nanomaterials. The National Toxicology Program, a part of the National Institutes of Health, recently agreed to conduct animal studies to investigate the effects of nanoparticles in the lungs and on the skin, and their uptake and distribution into and through the body.
Other agencies, including the Occupational Safety and Health Administration and the Food and Drug Administration, have also begun to pay attention to the field.
But compared to the federal investment in nanotech's "applications," the investment in the field's "implications" remains far too small, said Hope Shand, research director for ETC Group, an Ottawa-based research and advocacy organization that has called for a moratorium on commercializing nanotech products until governments adopt stricter oversight programs.
"Hundreds of nano products are on the market today, and there is no regulatory oversight to ensure that new manufactured nanomaterials are safe for human health and the environment," Shand said. "The U.S. government is spending nearly a billion dollars per year to promote nanotech. In comparison, EPA's new funding is like a nanodrop in the bucket."
Even revelations of health effects are unlikely to derail the nano-revolution, experts said. One recent promising study, by scientists at Rice University, has shown that it is possible to redesign nanoparticles to make them less toxic. If need be, said Karn of the EPA, existing regulations guiding conventional chemicals and workplace exposures can be made more stringent for nanomaterials.
Risk is not a matter of toxicology alone but also of exposure, safeguards and other factors, Karn noted, offering the example of gasoline.
"If you drink it, it kills you. If you put it in the water, it kills fish. And yet we use it every day, and nobody would think of banning gasoline just because it's toxic."