Nanotechnology involves the engineering and manipulation of materials, structures and devices on a nanometer scale & less than 100,000th the width of a human hair, said Howard. "At this ten to the minus seven to minus nine meter scale, many materials have unique and unusual properties," he noted.
Nanotechnology is one of the fastest growing technological areas in human history. "Carbon nanotubules were discovered in 1991 as excellent sources of field-emitted electronics, and by 2000 were being used commercially in a high-brightness light source to illuminate sports stadiums a jumbotron lamp. In contrast, it took 23 years between the modeling of the semiconductor property of germanium in 1931 and the commercialization of the first product, the transistor radio in 1954," said Howard.
He explained nanotechnology is already used in a number of products from dental-bonding agents to magnetic storage media and more applications will emerge in the next several decades, such as drug delivery systems, medical imaging applications, stronger, lighter and more durable materials, new defense technologies, miniature sensors, biomechanical and bioelectronics interfaces, new fuel and energy technologies and smaller computers.
"New technologies introduce new occupational health and safety hazards, and nanotechnology is no exception. Materials and devices are under development are so far from our current understanding that we can not easily apply existing paradigms to protecting workers. Perhaps for the first time, we need to understand the quantum properties of materials to which people are being exposed," he said. The U.S. National Science Foundation estimates that 2 million workers will be needed to support nanotechnology industries worldwide within 15 years. However, the number of people in secondary industries using nanotechnology-related materials and devices will be orders of magnitude greater.
"Very little is known currently about how dangerous nanomaterials are, or how we should protect workers in related industries," admitted Howard. "Research over the past few years has shown that nanometer-diameter particles are more toxic than larger particles on a mass basis. The combination of particle size, unique structures, and unique physical and chemical properties, suggests that a great deal of care needs to be taken to ensure adequate worker protection when manufacturing and using nanomaterials."
He said groups around the world are beginning to recognize the need to understand how nanotechnology will impact health and safety. In the United States, the National Nanotechnology Initiative (an interagency coordination group for nanotechnology research and development) places a strong emphasis on societal implications of nanotechnology. Consideration of the societal impact of nanotechnology is one of the 10 key aims of the United States National Nanotechnology Program established by an act of Congress in December of 2003: the 21st Century Nanotechnology Research and Development Act.
NIOSH's first significant research into the health risks associated with nanotechnology involved two preliminary studies of carbon nanotubes in 2002, said Howard. The research was carried out in partnership with NASA, Rice University and Carbon Nanotechnologies Incorporated, and studied the release of airborne nanoparticles from the raw material in the lab and workplace, as well as the material's toxicity. The two studies, published in November 2003 and January 2004, represent the first coordinated effort to understand the risks involved in handling a new and highly novel nanomaterial. In this case, NIOSH researchers were able to show that, although the nanotubes demonstrate cytotoxicity, they do not readily form a respirable aerosol when handled in a non-energetic way, Howard noted.
"NIOSH is uniquely positioned to investigate the health effects of nanoparticles based on its current work in welding, diesel, and beryllium ultrafine particles. For instance, NIOSH research has shown a close correlation between beryllium sensitization and the number concentration of nanometer-diameter beryllium particles," said Howard.
"From this start, NIOSH has been building an active nanotechnology program over the past few years. In February of this year, the NIOSH Nanotechnology and Health & Safety research program was launched under the National Occupational Research Agenda (NORA). This five-year initiative will study the toxicity and health impact of a range of nanomaterials. The program will primarily be focusing on the role of surface area as an exposure metric, the toxicity and health effects associated with carbon nanotubes and other nanomaterials, and the nature and control of occupational diesel emissions."
He said NIOSH is participating in the Nanoscale Science, Engineering and Technology subcommittee of the National Science and Technology Council, or NSET, and is a member of the National Nanotechnology Initiative. NSET and NNI are responsible for directing federal nanotechnology research within the US. As a participant in the NSET Committee of the NNI, the Committee plans to develop and issue through NIOSH, a "best practices" document for working with nanomaterials.
"Many industries and research organizations have a need for guidance on how to handle nanomaterials, and how to protect workers now," said Howard. "While we still don't know how harmful or benign these materials may be, it is important to provide basic information to manufacturers and users on how to minimize health risks based on what we do know now."
NIOSH is taking the lead through the interagency working group on nanotechnology and health to provide basic information on precautions that can be taken to reduce exposures through the appropriate use of control measures, personal protective equipment and good working practices. NIOSH is also co-sponsoring an international symposium on nanotechnology and occupational health with the UK Health and Safety Laboratory scheduled for Oct. 12-14 in Buxton, England.
