General Safe Practices for Working with Nanomaterials in Research Laboratories
Nanoparticles are particles that have at least one dimension between 1-100 nanometers. Nanoparticles may be naturally occurring or produced as unintentional by-products (such as in auto-emission). They may also be intentionally created or engineered.
We have a number of nanomaterial-related research projects carrying out on campus. Various nanomaterials are purchased from commercial suppliers or created from precursor materials in the laboratory under experimental procedures. These include carbon nanotubes, nanowires and sheets, fullerenes, quantum dots, carbon and metal-organic frameworks, metal or silica nanoparticles and other compounds.
Exposure to particulate nanomaterials can occur by inhalation, skin penetration or ingestion. Some particulate nanomaterials and their precursor materials may have inherent hazardous properties and may be classified as harmful, toxic, carcinogens or mutagens. There are concerns regarding potential risks to health that may arise during the fabrication, manipulation, use and disposal of these materials. However, only limited information is currently available on the toxicity of these engineered nanomaterials.
On campus, most laboratory researches involve handling nanoparticles in liquid solutions or other forms that will seldom become airborne, and freely formed nanoparticles tend to agglomerate to a larger size. In most researches, the amount of material used is small, generally less than a gram.
It is generally agreed that the current knowledge regarding the toxicity of particulate nanomaterial is incomplete and current safety data sheets may not adequately contain all the required safety information. Toxicity investigations indicate that the effects appear to be related to the size, dose, toxicity and also the total surface area of the nanoparticle. There are currently no statutory workplace exposure limits specifically for nanomaterials. NIOSH recommends that exposure to carbon nanotubes (CNT) and nanofibers (CNF) should be kept below the Recommended Exposure Limit (REL) of 1 μg/m3 of respirable elemental carbon as an eight-hour TWA (2013).
When research involves work with nanomaterial for which no toxicity data is yet available, it is prudent to assume the nanomaterial may be toxic, and hence it is essential that a precautionary approach be used when uncertainties are encountered.
In general, the potential risks to health from particulate nanomaterial can be reduced by safe handling and exposure control that limit inhalation, skin absorption, ingestion and injection. Whilst no single piece of guidance can provide a definitive, step-by-step approach to safe handling of all nanomaterials in all circumstances, there are a number of general as well as specific best practice guides that can be used in most applications.
- Furnaces or chemical reaction chambers used for engineered nanomaterials must be connected to dedicated exhaust ventilation. Use fume exhaust hood or dedicated local exhaust to exhaust any nanoparticles from tube furnaces or chemical reaction vessels.
- Work should be performed inside a laboratory fume hood at a minimum. Where gram quantities of nanomaterials are utilized in an exhausted enclosure, HEPA filtration or other means of treatment of the exhaust air may be necessary. Do not exhaust aerosols containing engineered nanoparticles inside buildings.
- To minimize airborne release of particulate nanomaterial to the environment, nanoparticles can be handled in solutions, or attached to substrates so that dry material is not released. When this is not feasible and the nanomaterials are in gram quantities, exhausted enclosures such as HEPA-filtered local capture hood or glove box are required.
The practices for working safely with nanomaterials are essentially the same as one would use when working with any research chemical of unknown toxicity.
Consideration and precautions should be taken in the following situations:
- When purchasing commercially available nanomaterials, be sure to obtain the Material Safety Data Sheet (MSDS) and to review the information in the MSDS with all students or assistants who will be working with the material. All personnel participating in research involving such materials need to be briefed on the potential hazards as well as on proper techniques for handling nanoparticles.
- In some researches, the fabrication of nanomaterials involves the use of chemicals that are known to be hazardous or toxic. Be sure to evaluate the hazards of the precursor materials and users should make themselves familiar with the known chemical's hazards by reading the MSDS or other hazard information.
- Practice good environmental hygiene. Wet wipe work surfaces such as benchtops where nanomaterials, fibers or solutions have been handled at the end of each day. Surface contamination with particulate nanomaterials may not be visible.
- Wear double gloves, safety goggles and appropriate protective clothing for handling dry or liquid materials. When nanomaterials are present in a solvent carrier, glove should be selected based on the suitability of the glove for protection against the particular solvent.
- Use standard precautions when liquid phase nanomaterials are used in biological research procedures.
- Wear approved respirator filters that are rated as N-, R- or P-100 (HEPA) for respiratory protection where airborne exposure to particulate nanomaterials is anticipated, e.g. cleanout of systems used for the growth of nanomaterial like carbon nanotubes or metal particulates. HSEO will work with researchers to provide the most appropriate type of respirator.
- Equipment used to create or handle nanomaterials should be cleaned or evaluated for potential contamination prior to disposal or reuse. Laboratory equipment and exhaust systems should be evaluated prior to repair or removal and equipment maintenance staff need to be alerted to the potential exposure to nanoparticles.
- Dispose of and transport waste nanomaterials in solution according to the hazardous waste procedures for the solvent. All waste nanomaterials should be treated as unwanted hazardous “toxic” materials unless it is known to be non-hazardous. If you have questions on how to dispose of a specific nanomaterial waste, contact HSEO for more information and advice.
- Spills of nanomaterials are to be cleaned up right away. The person cleaning up the spill should wear double gloves and vacuum up the area with a HEPA filtered vacuum or wet wipe the area with towels or clean the spill using a combination of the two methods. For spills that might result in airborne nanoparticles, proper respiratory protection should be worn. For assistance with cleaning up any spill, contact HSEO.
- Other good laboratory practices including labeling of containers with the full chemical name or name of mixture, hand washing, good personal hygiene, no eating or drinking in the laboratory, etc., should also be followed.
For more information on health and safety of nanotechnology, you can visit the following websites:
Chapter 21 Nanomaterial and Nanotechnology HSEO Safety Manual
NIOSH – Workplace Safety and Health Topics: Nanotechnology