Exposure to nanomaterials may occur through inhalation, dermal contact, or ingestion, depending on how personnel use them. The full health effects of exposures to nanomaterials are not fully understood. For example, a peer-reviewed toxicity study on carbon nanotubes (CNTs) indicated that the toxicity of nanoparticles depends on specific physiochemical and environmental factors, and thus the toxic potential of each nanoparticle needs to be evaluated separately.⁹ Results of existing studies on animals or humans provide some basis for preliminary estimates of areas of concern.

According to the National Institute for Occupational Safety and Health (NIOSH)², studies to date have indicated:

• Increased toxicity of ultrafine particles or nanoparticles as compared to larger particles of similar composition. Chemical composition and other particle properties can also influence toxicity.^{19, 20, 21, 24, 15, 29, 4, 7, 3, 16, 6}
• A greater proportion of inhaled nanoparticles will deposit in the respiratory tract, as compared to larger particles.^{11, 12, 5, 13}
• Nanoparticles can cross cell membranes and interact with subcellular structures, where they have been shown to cause oxidative damage and impair function of cells in culture.^{17, 18, 10}
• Nanoparticles may be capable of penetrating healthy intact skin and translocating to other organ systems following penetration.^{28, 14, 22, 23, 27, 10}
• Catalytic effects and fire or explosion may present hazards.²⁵

Training

• Ensure that researchers have both general safety training and lab-specific training relevant to the nanomaterials and associated hazardous chemicals used in the process or experiment. See the safety training section for guidance on training.
• Lab-specific training can include a review of this safety fact sheet, the relevant safety data sheets (if available), and the lab’s standard operating procedure for the experiment.

Standard operating procedures

• Prepare a standard operating procedure (SOP) for operations involving nanomaterials. For guidance on creating SOPs, see the SOP section. The SOP should be specific to the proposed procedure.
• Consider the hazards of the precursor materials in evaluating the process.
• Special consideration should be given to the high reactivity of some nanopowders with regard to potential fire and explosion.

Consultation

• Consult with the PI prior to procuring or working with nanomaterials.
• Review the Chemical Safety section on consultation and prior approvals.
• For additional assistance, contact EH&S’s Occupational Health & Safety Program at (650) 723-0448.

Exposure standards have not been established for engineered nanoparticles in the United States or internationally.²⁶ Until more definitive findings are made regarding the potential health risks of handling nanomaterials, researchers planning to work with nanomaterials must implement a combination of engineering controls, work practices, and personal protective equipment to minimize potential exposures to themselves and others.

For a quick guide to the exposure risks and prudent control measures to be used for common laboratory operations involving nanomaterials, refer to the table in the Exposure Risks and Control Measures for Common Laboratory Operations tab. It’s important to consider if the nanoparticles are in an agglomerated or aggregated form, functionalized, suspended in liquid, or bound, as these conditions may affect the exposure potential.

Engineering controls

• Use glove bags, glove boxes, fume hoods, or other containment or exhausted enclosures when there is a potential for aerosolization, such as:
  • Handling powders
  • Creating nanoparticles in gas phase
  • Pouring or mixing liquid media which involves a high degree of agitation. (Do not use horizontal laminar flow hoods (clean benches), as these devices direct the air flow towards the worker.) Consult with EH&S if engineering controls are not feasible.
• Use fume hoods or other local exhaust devices to exhaust tube furnaces and/or chemical reaction vessels.
• Perform any maintenance activities, such as repair to equipment used to create nanomaterials or cleaning/replacement of dust collection systems, in fume hoods or under appropriate local exhaust.

Work practices

Selection of nanomaterials

• Whenever possible, handle nanomaterials in solutions, or attached to substrates, to minimize airborne release.
• Consult the safety data sheet (SDS), if available, or other appropriate references prior to using a chemical or nanomaterial with which you are unfamiliar. Note that information contained in some MSDSs may not be fully accurate and/or may be more relevant to the properties of the bulk material, rather than the nano-size particles.

Safety equipment

Know the location and proper use of emergency equipment, such as safety showers, fire extinguishers, and fire alarms.

Hygiene

• Do not consume or store food and beverages or apply cosmetics where chemicals or nanomaterials are used or stored, since this practice increases the likelihood of exposure by ingestion.
• Do not use mouth suction for pipetting or siphoning.
• Wash hands frequently to minimize potential chemical or nanoparticle exposure through ingestion and dermal contact.
• Remove gloves when leaving the laboratory so as not to contaminate doorknobs, or when handling common use objects such as phones, multiuser computers, etc.

Labeling and signage

• Store in a well-sealed container that can be opened with minimal agitation of the contents.
• Label all chemical containers with the identity of the contents. Avoid abbreviations or acronyms. Include “nano” in the descriptor (i.e. label as “nano-zinc oxide particles” rather than “zinc oxide”). Include hazard warning and chemical concentration information, if known.
• Use cautious judgment when leaving operations unattended:
  • Post signs to communicate appropriate warnings and precautions.
  • Anticipate potential equipment and facility failures.
  • Provide appropriate containment for accidental release of hazardous chemicals.

Cleaning

Wet wipe and/or HEPA-vacuum work surfaces regularly.

Transporting

Use a sealed, double-contained container when transporting nanomaterials inside or outside of the building.

Buddy system

Communicate with others in the building when working alone in the laboratory. Let them know when you arrive and leave. Avoid working alone in the laboratory when performing high-risk operations.

Spill response

In addition to following EH&S general spill response directions, integrate these additional measures for spills involving nanomaterials:

• Use wet cleanup methods or vacuum cleaners equipped with HEPA-filters.
• Do not dry sweep or use conventional vacuum cleaners.
• Collect spill cleanup materials in a tightly closed container.
• Manage spill cleanup debris as hazardous waste.

Disposal

As a prudent measure, manage nanoparticle wastes, including contaminated lab debris, as a part of your normal laboratory hazardous waste stream.

Collect and store waste materials in a tightly closed container. Include information describing the nanoparticulate nature of the materials on the waste tag (e.g. “contains nanosilver material”).

Personal protective equipment

• Wear gloves, lab coats, safety goggles, long pants, closed-toe shoes, and face shields, as appropriate, based on the nature of the materials and procedure.
• If work cannot be conducted inside a fume hood or other ventilated enclosure, consult with EH&S’s Occupational Health and Safety Program regarding the need for respiratory protection or other alternative controls.

Use this table to assess exposure risks and to implement control measures for common lab operations involving nanomaterials.

* EH&S recognizes that low-density nanomaterials (e.g. carbon-based) become aerosolized by even the slightest air movement and may not be practical when weighed or handled in laboratory fume hoods. Consult with EH&S on alternative sets of controls.

[1] National Institute for Occupational Safety and Health (NIOSH) Approaches to Safe Nanotechnology: Managing the Health and Safety Concerns Associated with Engineered Nanomaterials (March 2009).  https://www.cdc.gov/niosh/docs/2009-125/

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