Accident Prevention Manual for Business & Industry: Engineering & Technology 13th edition National Safety Council Compiled by Dr. S.D. Allen Iske, Associate Professor University of Central Missouri

CHAPTER 14 NANOPARTICLES

Nanotechnology Collection of technologies dealing with materials science on the nanometer scale. Special concerns: inhalation hazard for humans free unbound nanoparticle and nanofiber materials absorption routes into the body (skin, lungs, blood, brain, and other target organs) comprehensive hazard assessment

Historical Perspective Nanoparticles are not a new phenomenon. Scientists were aware of colloids and sols, for more than 100 years. The scientific investigation of colloids and their properties was reported by Faraday (1857) in his experiments with gold. He used the term “divided metals” to describe the material which he produced. Zsigmondy (1905) described the formation of a red gold sol which is now understood to comprise particles in the 10 nm size range.

Definitions/Sizes Nanotechnology involves the creation and/or manipulation of materials at the nanometer (nm) scale either by scaling up from single groups of atoms or by refining or reducing bulk materials. A nanometer is 1 x m or one millionth of a millimeter. A human hair is 10,000 to 50,000 nm, a single red blood cell has a diameter of around 5000 nm, viruses typically have a maximum dimension of 10 to 100 nm and a DNA molecule has a diameter of 2–12 nm (

Nanomaterials Ordinary materials such as carbon or silicon, when reduced to the nanoscale, often exhibit novel and unpredictable characteristics: extraordinary strength, chemical reactivity, electrical conductivity, or other characteristics that the same material does not possess at the micro or macro-scale A huge range of materials have already been produced including nanotubes, nanowires, fullerene derivatives (bucky balls), and other nanoscale materials.

Categories and Applications Nanostructure Nanotubes Nanowires Nanocrystals Other nanoparticles Example Material or Application carbon, (fullerenes) metals, semiconductors, oxides, sulfides, nitrides quantum dots insulators, semiconductors, metals, magnetic materials ceramic oxides, metals

Current Status Limited current knowledge Industrial applications growing rapidly Professional and regulatory agencies interest and methods of assessment increasing Workplace hazards versus atmospheric emissions for exposure

Knowledge Gaps The nanoparticle nomenclature is not sufficiently well described. There are no convenient methods by which exposures to nanoparticles in the workplace can be measured or assessed. There is insufficient knowledge concerning nanoparticle exposure. The effectiveness of control approaches has not been evaluated. Knowledge concerning nanoparticle risks is inadequate for risk assessments.

Use at Worksite Occupational exposure control prior to introduction Examine toxicity and dose data

Nanomaterials in Workplace Investigate and determine physical and chemical properties per potential toxicity Evaluate short and long-term effects on organ systems Determine biological mechanisms for toxic effects Create and integrate models in assessing possible hazards Determine if mass or other property informs toxicity impact

Measurement Methods Important for accuracy and protective measures Evaluate methods of measuring respirable particles in the air and application to nanomaterials Develop and field test practical methods to measure airborne nanomaterials Develop testing and evaluation systems to compare and validate sampling instruments

Preparing Workplace Exposure assessment - worksite and workers for exposure potentials Machine and plant floor Cleaning crews Finished product testing Packaging Spray applications Particle size and absorption properties

Risk assessment Potential exposure to nanomaterials Determine current exposure-response data (human or animal) to identify and assess potential occupational hazards Develop framework for evaluating and predicting potential occupational risk to exposure of nanomaterials

Monitoring Results Epidemiology and surveillance—measurements of consequences of nanomaterials use Evaluate existing workplace studies with nanomaterials. Identify knowledge gaps of understanding of nanomaterials and conduct new studies. Integrate health and safety issues in existing surveillance methods and additional screening methods. Use existing systems data and information.

Engineering Controls and PPE Employers legal duty and practical obligation to utilize protections—preventing harm to workers Control methods Ventilation systems, clean rooms, glove box, respiratory protection, face shields, clothing—minimize air and skin exposures to nanomaterials to prevent harmful effects

Protection Controls Research Evaluate effectiveness of engineering controls in reducing occupational exposures—nanoparticles or nanoaerosols. Evaluate and improve PPE. Develop recommendations to prevent or limit exposures (e.g., respirator fit testing). Evaluate control banding techniques, information gaps, and effectiveness of alternate. methods

Explosion and Fire Risks Identify physical and chemical properties that contribute to dustiness, combustibility, flammability, and conductivity of nanomaterials. Recommend alternative work practices to eliminate or reduce workplace exposures. Develop a disposal protocol reducing potential for harm to workers in waste-handling systems.

Regulatory Issues Agencies to evaluate current regulatory requirements for nanomaterials for worker protection from exposures: National Institute for Occupational Safety and Health (NIOSH) Occupational Safety and Health Administration (OSHA) U.S. Environmental Protection Agency (EPA)