Nanomaterials Handling Safety Guide for Laboratories
- Applicability and Scope
- “Precautionary Principle” for Engineered Nanomaterials
- Standard Operating Procedures (SOPs)
- Nanomaterial Specific Material Safety Data Sheet (SDS)
- Hazard Assessment
- Exposure Monitoring
- Routes of Nanomaterials Exposure to Human Body
- Engineering Controls
- Personal Protective Equipment (PPE)
- Work Area Designation
- Labeling Containers
- Spill Cleanup
- Waste Management
1. Applicability and Scope
- This laboratory safety guidance (LSG) complies with the “precautionary principle” for handling nanomaterials (NMs). In the absence of NM specific regulatory standards or other exposure standards (OSHA PELs, NIOSH RELs and ACGIH TLVs) and EPA regulations for waste collection and disposal, this LSG should be implemented by the laboratory researchers who perform experiments involving NMs.
- Typically, nanomaterial safety (nanosafety) in a research laboratory applies to engineered nano-sized materials only and does not apply to bulk micro-sized materials, bacteria, viruses, DNA, consumer products, etc. However, if NMs are treated or impregnated with the above mentioned biological organisms, tissues or are used in laboratory animals, then both nanosafety and biosafety procedures (or whichever is most stringent) will be implemented to protect the researchers and the environment.
- Nanotechnology: Nanotechnology is a multidisciplinary science and technology and encompasses physical, chemical, biological, engineering and electronic processes.
- Nanomaterial (NM): nano-sized material having at least one external dimension in the size range of 1-100 nanometers. NMs include nanoparticles (NPs), nanostructured materials and ultrafine particles, and their agglomerates and aggregates.
- Nanoparticle (NP): NM having all three external dimensions in the size range of 1-100 nanometers and its physicochemical properties are distinctly different than its bulk material of the same composition.
- Nanostructured material: NM having distinct structural elements with dimensions in the size range of 1 to 100 nm. Nanostructured materials include nano-sized clusters, nano-crystallites or molecular composites.
- Ultrafine particles: aerosolized NMs including incidental NPs derived from aerosols and their agglomerates are defined as ultrafine particles.
- Agglomerates: group of NPs held together by weak interactions, such as van der waals forces, electrostatic forces and surface tension such that NPs are separated relatively easily with mild perturbation.
- Aggregates: heterogeneous NPs in which various components are not easily separated as they are held together by relatively strong forces.
3. “Precautionary Principle” for Engineered Nanomaterials
- “In the absence of complete scientific evidence, the potential threat of research materials on human health and the environment is assumed to be such that precautionary measures must be taken until the material is known to be safe. Lack of scientific certainty or cause and effect relationships should not be used as a reason for postponing reasonable measures that could prevent human exposure and environmental release” (16.1, 16.2).
- NMs can impart greater toxicity than micro-sized bulk materials of the same composition.
- NMs in insoluble form(s) can impart greater toxicity in the human body than micro-sized materials of the same chemical composition that are solubilized in water.
- NMs with fresh active surfaces are more reactive than encapsulated or passivated NMs (treated to reduce chemical reactivity of surface).
- Unbound or free NPs can pose a more severe health hazard than the bound or embedded NMs.
- The duration, magnitude of exposure, and persistence of NMs in the human body can have adverse health effects.
4. Standard Operating Procedures (SOPs)
- Researchers working with NMs should develop and implement written laboratory SOPs. The written SOPs should include environmental health and safety components such as PPE and respiratory protection, waste collection and disposal, and transportation of materials within the university and outside the university.
- Laboratory SOPs should be periodically reviewed and updated for effective control of potential hazards arising from NMs handling.
5. Nanomaterial Specific Safety Data Sheet (SDS)
- Each research laboratory should maintain a „Nanomaterial Inventory‟ and NM-specific SDSs. A blank NM inventory sheet is included in Appendix A.
- SDSs should be reviewed prior to handling the NMs in a research lab.
- If a NM-specific SDS is not available, then the researcher should request one from the supplier or manufacturer.
- NM-specific SDSs must include product description, hazard identification, composition, physicochemical characteristics, fire fighting measures, accidental release measures, handling and storage, exposure controls/personal protection and disposal considerations.
6. Hazard Assessment
- A hazard assessment should be performed to control and minimize the exposures to research staff and laboratory environment.
- The hazard assessment includes evaluation of material identity, process description, availability of engineering controls, typical quantity of NMs used per operation, anticipated airborne concentration levels outside the engineering controls (if any), duration and frequency of exposure, and toxicity levels. A hazard assessment data capture form is included in Appendix B (see section 10.3 for additional information).
- A holistic approach for the control of hazardous NMs exposure in research lab is given below.
7. Exposure Monitoring
- Traditional bulk air sampling NIOSH/OSHA methods that measure mass per unit volume of air (mg/m3, or as ppmv) will provide very limited information about the airborne concentrations of NMs.
- Real time particle counters (optical and condensation particle counters) that measure count per unit volume (#/m3) are preferred for monitoring the airborne NPs.
- Electron scanning microscopy, transmission electron microscopy and atomic force spectroscopy analyses of wipe samples are preferred to evaluate the surface contamination and particle characterization.
- Examples of real time optical and condensation particle counters available from different manufacturers are shown below:
8. Routes of Nanomaterials Exposure to Human Body
- Inhalation of NPs can result in pulmonary inflammatory reactions in the lung. Also, NPs can translocate from the lungs to other parts of the human body, including the brain.
- Due to lack of information associated with the dermal exposure to NPs, skin including face and forearms should be protected.
- Accidental ingestion can lead to the transfer of NMs from gastrointestinal walls to liver and kidney (16.10).
- Potential hazards, exposure to human body and risk-level from different matrices are identified below.
9. Engineering Controls
- Perform NMs work within chemical fume hoods, hard-ducted biosafety cabinets (BSCs), enclosure hoods or glove boxes.
- Handling of dry solid NMs on the lab bench is not permitted without a local capture hood that is exhausted through a HEPA filter.
- For most applications, greater than 100 milligram quantities of NMs can be safely weighed in a fume hood or enclosure hood without significant changes in accuracy resulting from potential air turbulences. Simple steps such as the use of glass bottles or volumetric flasks and “fish-tank” enclosures can minimize the air turbulence.
- If a balance cannot be located in a fume hood for weighing powders, tare the weighing bottle with a stopper, add the NM powder into the weighing bottle and stopper the bottle inside the fume hood, then return the bottle to the balance for final weighing.
- Generation of NM-containing aerosol outside of the engineering controls must be controlled. In general, BSCs with recirculation of exhaust air into the laboratory should not be used for NMs handling. If use of a recirculating BSC is desired, a hazard assessment must be done prior to doing the work to determine if this is acceptable.
- NMs embedded in polymer composites should be handled within engineering controls to minimize the process-related fugitive emissions from grinding, thinning, dimpling, ion mill polishing, etc.
- Laboratory animal studies including dosing, perfusion and necropsy should be conducted within engineering controls, such as chemical fume hood, BSC, workbench equipped with the local capture hood, elephant trunk etc., and exhausted outside the building.
- Chemical composition, structural property including morphology, quantity and concentration levels of NMs, and formulation of excipients (inactive diluents/carriers) may vary with each animal study protocol. Therefore, safety control measures must be addressed in each protocol and reviewed by the animal care personnel for safe handling of animals, animal bedding, and animal wastes (excreta) etc.
- Fume hoods, local capture hoods and vacuum devices may require HEPA filtration for handling NMs depending on the aerosol generation potential, quantity of aerosol/dust generation and toxicity levels. General recommendations for HEPA filtration of the exhausted air are given below.
10. Personal Protective Equipment (PPE)
- Basic PPE and Hygiene
- 10.1.1 Safety glasses and lab coat or coverall are required while handling NMs.
- 10.1.2 Nonwoven coverall (such as Tyvek suits) are recommended to protect the skin while handling animals and during the wet chemical synthesis of NMs.
- 10.1.3 Wash hands after handling NMs to prevent accidental ingestion.
- 10.1.4 Eating, drinking or chewing is not allowed in laboratories.
- 10.2.1 Irrespective of the matrices used, nitrile or better rated gloves should be worn while handling NMs, nanoparticles and nanostructured materials and their agglomerates or aggregates.
- 10.2.2 Replace the gloves as frequently as needed. Double-gloves are strongly recommended while working with concentrated solutions.
- 10.2.3 Inspect the gloves for perforation, etc. before use and prevent needle stick related skin-punctures from injectable solutions.
- 10.3.1 Whenever dry NM is handled outside the fume hood, a dust mask (N95 dust mask or better) should be worn and researchers may require fit testing for dust masks.
- 10.3.2 If the use of a dust mask or elastomeric/rubber mask is required, then a detailed hazard assessment and medical evaluation must be completed prior to respirator implementation.
- 10.3.3 A copy of the hazard assessment along with the written SOP must be submitted to EHS for review. A blank NM hazard assessment form can be obtained from your EHS safety advisor or downloaded from EHS website (Appendix B).
- 10.3.4 EHS will recommend a particulate-filtering elastomeric half face piece respirator or full-face piece respirator under the “required respirator use” program, only after reviewing the hazard assessment data.
- 10.3.5 When handling NMs within a fume hood or an enclosure hood, an N95 dust mask can be worn as extra protection on a voluntary basis.
11. Work Area Designation
- NMs work should be performed within a designated area.
- An example of caution notice to define the designated NMs work area is shown below.
12. Labeling Containers
- Primary containers should be labeled for laboratory-generated NMs. Primary container information should include “Nano Chemical Name”, solvent name (for dispersed solutions), concentration or quantity and contact person name. Examples of labeling language are given below:
- At a minimum, reaction flasks and small storage vials, centrifuge tubes, etc., and secondary containers should include the material identity, researcher name and date of preparation. Examples are given below:
13. Spill Cleanup
- Laboratory surfaces, fume hood or enclosure hood surfaces should be wet-wiped after each use or at least at the end of the workday.
- PPE including safety goggles, gloves, and lab coat will be required for NM spill cleanup. A respirator such as dust mask (N95 or better), HEPA vacuum and sticky mat are recommended but not required for a small incidental spill cleanup.
- Wet-wipe method using water-moist absorbent towels such as Bounty® paper towels is the preferred method of cleaning for NMs to prevent generating airborne particles.
- Nano-sized materials (such as iron metal nanopowder) have a greater potential for fire and explosion than the larger sized micro particles of the same chemical because of the increased surface area and greater reactivity. NMs including carbon nanotubes and metal particles can burn and explode in presence of oxidants such as air and an ignition source. Therefore, appropriate precautions should be taken.
- Do not dry-sweep or use compressed air for NMs cleanup. If required, a HEPA filtered vacuum should be used for dry-powders and the HEPA filtered air should be exhausted outside through a fume hood or local capture hood. This is recommended because nano-sized particles possess both solid-like and like gas-like properties, and HEPA filters may not be very effective in capturing the gas-like nanoparticles.
- As part of the equipment decommissioning/decontamination procedure, equipment used to create or handle the NMs should be cleaned or decontaminated prior to maintenance, repair or disposal.
14. Waste Management
- Though EPA has not promulgated NM specific regulations for waste disposal, many NMs may contain toxic components that are regulated. Therefore, every effort should be made by the researchers to prevent the release of NMs to the environment to the greatest extent feasible and comply with regulatory standards. Researchers must follow EHS protocols for management and disposal of chemical waste.
- NM-containing waste should be treated as hazardous waste. Laboratory generated NMs waste must not be disposed of in the regular trash or down the drain.
- NM-containing wastes including NM dispersions must be disposed of through EHS.
- NMs waste may be stored in a fume hood until ready for pickup, but must be stored in a closed container.
- Gloves, sharps and needles should be disposed of as bio-hazardous waste.
- NM contaminated coveralls should be disposed of as hazardous waste.
- Unused NM solids and NM dispersed solutions must be identified on the hazardous waste label.
- An example of hazardous waste label is given below.
- Primary storage containers made of glass are preferred for the storage and transport of NMs (glass reduces electrostatic charges that can cause dry materials to become easily airborne when opening the container).
- Sealed secondary containers should be used to transport NMs/solutions between labs.
- The use of secondary containers made of shatter proof plastics is recommended to prevent the accidental breakage of primary glass containers during transport between labs.
- DOT regulations must be followed for the transportation of NMs to off-site locations within the university and outside of the university.
- The SDS should be included in packages for NM shipment to outside institutions.
- Critical Issues – Nanomaterials: What are the Environmental and Health Impacts, by Nastassia Lewinski.
- OSEH SOP on Engineered Nanomaterials, University of Michigan, May, 2010.
- Series on the Safety of Manufactured Nanomaterials No. 28. Compilation of nanomaterial exposure mitigation guidelines relating to laboratories.
- A review of the toxicity of particles that are intentionally produced for use in nanotechnology applications, seen from an occupational health perspective. Industrial Chemicals Unit, HSE, 2004.
- Approaches to Safe Nanotechnology Managing the Health and Safety Concerns Associated with Engineered Nanomaterials.
- Anna Giulia Cattaneo, Rosalba Gornati, Enrico Sabbioni, Maurizio Chiriva-Internati, Everardo Cobos, Marjorie R. Jenkins and Giovanni Bernardini, Nanotechnology and human health: risks and benefits. J. Appl. Toxicol. 2010, 30: 730–744.
- Amela Groso, Alke Petri-Fink, Arnaud Magrez, Michael Riediker and Thierry Meyer. Management of nanomaterials safety in research environment. Particle and Fibre Toxicology 2010, 7:40.
- Welcome to the GoodNanoGuide.
- NIOSH Safety and Health Topic: Nanotechnology Informational & Educational Materials.
- Lin Wang, Dattatri K Nagesha, Selvapraba Selvarasah, Mehmet R Dokmeci, and Rebecca L Carrier. Toxicity of CdSe Nanoparticles in Caco-2 Cell Cultures. Journal of Nanobiotechnology 2008, 6:11