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Ahead of the curve

May 1, 2011

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Although research on nanomaterials is still evolving, employers are taking precautionary steps to prevent worker exposures

By Ashley Johnson, associate editor

KEY POINTS
  • Nanomaterials have not been linked to any acute, adverse health problems in workers; however, laboratory studies of animals have raised concerns about the toxicity of carbon nanotubes.
  • Best practices identified by NIOSH and employers include respirators, medical surveillance, source enclosure, ventilation systems and protective clothing.
  • Classifying the seemingly endless varieties of nanomaterials presents a challenge to future regulations.

Considered a budding field 10 years ago, nanotechnology – the science of manipulating materials at the molecular level – is being applied in just about every industry, from defense and automotives to cosmetics. Nanotechnology could even hold the key to future environmental and medical breakthroughs.

But as scientists and manufacturers seek to harness the promise of nanotechnology, questions remain about the potential risks to workers who handle the tiny materials.

Richard Denison, senior scientist with the Environmental Defense Fund, an advocacy group based in New York, noted it can take decades to detect health effects and link them to a particular substance or exposure.

“One of the opportunities we have with nanomaterials, generally, I think is to get ahead of the curve,” Denison said. “That is, not to wait to do anything – to do research, to set limits – not to wait until we have definitive evidence that these materials are harming workers or people or the environment, but rather to put in place proactive measures that can reduce exposure because of the potential for these materials to cause harm.”

In 2007, the Environmental Defense Fund and DuPont published a framework to help organizations approach risk management during the commercialization process. With innovation in nanotechnology outpacing data and regulation, employers continue to partner with each other and government agencies to develop best practices for protecting workers.

Small wonder

Charles Geraci, coordinator of the NIOSH Nanotechnology Research Center, said nanotechnology is critical for the nation and the economy. “It really is the new way of doing material science,” he said.

Nanomaterials range in size from 1 to 100 nanometers. To put that in perspective, 1 nanometer is 1 billionth of a meter. A distinction is made between nanoscale materials that occur naturally in the human body or through processes such as erosion and engineered nanomaterials, which are purposefully manufactured at the nanoscale for various applications.

Concern surrounds engineered nanomaterials because objects behave differently when reduced to nanoscale. For instance, a material such as aluminum is relatively stable at bulk scale, but can become highly reactive or even explosive at nanoscale proportions.

Beyond combustion, nanomaterials may pose health risks to workers who inhale or otherwise come into contact with them during research or the manufacturing process. In fact, laboratory animal studies indicate a link between exposure to carbon nanotubes and respiratory problems. Such findings prompted NIOSH in December to release a draft current intelligence bulletin on carbon nanotubes and nanofibers containing recommended exposure limits.

But nanomaterials currently have not been proven to cause acute, adverse health effects among workers, according to Sally Tinkle, deputy director of the National Nanotechnology Coordination Office, which is under the White House National Science and Technology Council.

“It doesn’t mean we should be any less vigilant or any less careful,” she said. “We need to retain that high level of care in protecting our workers, but so far, so good.”

Tinkle works with federal agencies to coordinate environmental health and safety research within the National Nanotechnology Initiative, a program established in 2001 to steer research and development efforts.

President Barack Obama’s budget request for fiscal year 2012 allocates $2.1 billion to NNI, including $123.5 million for EHS research across agencies including NIOSH.

In the past, NNI has been criticized for not investing enough in safety research and failing to put forth an implementation plan identifying costs and responsibilities for each agency. However, Tinkle said that is not NNI’s role. She described a “disconnect” between the job of NNI and stakeholder expectations: NNI creates a framework for how research should be integrated; federal agencies develop their own implementation plans.

To help develop a plan more in line with stakeholders’ expectations, Tinkle said NNI consulted them while developing the new strategic plan, released in February.

‘Not starting at absolute zero’

Questions abound about assessing the risks of nanoparticles. For example, should focus be on the number of nanomaterial particles in an exposure, particle size or the chemical properties of the particle? 

“There are a lot of unknowns here specific to the materials,” Geraci acknowledged. “But what is not unknown is how to do risk management, how to understand the possibility for worker exposure and how to control that.” Citing work with pharmaceuticals and dry powder detergents, he said, “We’re not starting at absolute zero here. It really is a re-application of a lot of knowledge that is already available.”

In 2005, NIOSH issued a guidance document, “Approaches to Safe Nanotechnology.” Updated twice since then, the guide recommends practices to prevent exposure, such as source enclosure, ventilation systems, protective clothing and respirators.

Geraci, one of the primary authors of the guide, is part of a NIOSH team that visits nanomaterial producer sites. Overall, “They’re taking a good, proactive stance on protecting their employees,” he said. The challenge for NIOSH is refining the guidance to address the specific materials companies are making and handling, as well as the processes involved.

One company taking a proactive approach is Nanocomp Technologies Inc. The Concord, NH-based company, which manufactures carbon nanotube materials, started working with NIOSH early in the research and development phase.

Mark Banash, vice president for quality and regulatory affairs at Nanocomp, summed up its approach to safety: “We ruthlessly monitor our processes. We ruthlessly monitor our site for the presence of nanomaterials.”

Banash said carbon nanotubes typically are made as powders, but Nanocomp grows them in fibers, which eliminates safety issues associated with loose powders. Workers are required to wear respiratory protection when they harvest materials out of the reactor even though Nanocomp has never detected the release of nanomaterials.

After eight years in the field, Banash has noticed a larger emphasis on EHS among employers. “You’re starting to see the change in the industry where what were startups and what were professors working out of their labs, you’re seeing them now become businesses, true manufacturing places,” he said. “And with that, you’re seeing a very real awareness of EHS in the nanomaterials industry, and I think that’s going to continue.”

Constant research 

Dr. Peter Lichty is the occupational medical director at the Lawrence Berkeley National Laboratory, a Department of Energy lab in California where researchers develop new types of engineered nanoparticles.

He said the laboratory developed bench-top hoods with a HEPA filter exhaust that can be placed over equipment such as a scale to prevent dry nanomaterials from escaping into the room. However, Lichty questions whether health monitoring will reveal all of the effects associated with nanomaterials.

“That’s the big question – what types of health effects are we looking for, and is there a medical test that will detect it?” he said. “And to me, that says that there is no battery of tests that will apply to all engineered nanoparticles.”

Instead, scientists likely will have to tailor their surveillance examinations as they learn more about the specific health effects of individual particles, he said.

In the meantime, employers look for ways to keep up with constantly evolving research.

Brendan McKenney, director of operations for Santa Ana, CA-based QuantumSphere Inc., said funding environmental and toxicology studies can be a challenge for small companies. QSI takes advantage of the information and free programs offered by NIOSH and the California Environmental Protection Agency.

“We take a pretty proactive approach to being on the front line and learning as much as we can,” he said.

To help the U.S. Air Force stay current on nanomaterials research, Roanoke, VA-based Luna Innovations Inc. developed a web portal system that provides up-to-date EHS information.

Luna also emphasizes safety at its own nanomaterials facility with strict procedures for materials handling, personal protective equipment, periodic safety reviews and a dust collection system designed to capture particles down to 1 nanometer, according to Charles Gause, senior vice president of corporate development at Luna.

“There are still many unknowns, but with the high volume of research being done worldwide, we are working to develop effective information tracking within the nanomaterials industry,” Gause said.

Classification conundrum

As data on nanomaterials improves, Bill Kojola, industrial hygienist for the AFL-CIO Department of Occupational Safety and Health, believes specific regulations addressing worker exposures will be necessary.

“I have some concerns long-term about whether or not we may see down the line workers getting sick from those exposures,” he said. “I’m very dubious about industry policing itself. I think there are some employers that will do a good job and many won’t.”

As for current protections, Kojola doubts some workers have been told they are working with products that contain engineered nanomaterials. “I think there’s a real breakdown in transferring that information and knowledge to workers,” he added.

In January, the International Organization for Standardization adopted a standard for inhalation toxicity testing of nanotechnology-based products. The voluntary standard aims to ensure reliability and harmonization of test results worldwide.

Although OSHA does not have any specific regulations for nanomaterials, U.S. agencies are looking into the issue. Tinkle noted that OSHA, the Food and Drug Administration, the Environmental Protection Agency and the Consumer Product Safety Commission each require different types of data to conduct risk assessments and promulgate regulation.

Even though it seems data is lagging, “This is normal in the scientific process,” she said. “This is not special to nanoparticles.”

What is unique is the sheer diversity of materials, which Tinkle, Denison and Geraci agree presents a challenge for classification.

“We are looking into the work and the research that is needed to take a broader category approach to understanding and managing these materials,” Geraci said. “I think a lot of people around the world realize that there aren’t enough dollars and enough people to do individual tests of every single nanoparticle that’s created.”

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