Nanomaterials

Description

Nanomaterials are engineered materials that have at least one external dimension less than 100 nm and properties that differ from the bulk material. Materials with all three dimensions under 100 nm are referred to as nanoparticles. The table below lists some common nanomaterials:

Type

Examples

Carbon-based

Buckyballs, fullerenes, carbon nanotubes, dendrimers

Metals and metal oxides

Titanium dioxide (titania), zinc oxide, cerium oxide (ceria), aluminum oxide, iron oxide, silver, gold, zero valent iron nanoparticles

Quantum dots

ZnSe, ZnS, ZnTe, CdS, CdTe, CdSe, GaAs, AlGaAs, PbSe, InP

Biological materials such as protein, DNA, or RNA are NOT nanomaterials.

Overview of Hazards 

Because nanomaterial properties differ from those of the bulk material, their toxicity and health effects can be very different. Their small size allows them to enter the body easily, and the higher surface area can make them particularly reactive and/or toxic. Because engineered nanomaterials are a relatively new area of study, the health effects are not fully understood. Moreover, the effects vary with the material as the composition of the nanomaterial affects how it can enter the body. There is evidence that nanomaterials deposit in the lungs, penetrate intact skin, and enter the blood stream, through which they can translocate to any organ including the central nervous system. The long-term health effects of such exposures are not known. 

Exposure to Nanomaterials

The greatest risk of exposure is through inhalation of airborne nanomaterials. The amount of material released depends on the type of nanomaterial and how it is being used. The following table lists three common forms and their potential for release of airborne nanomaterials: 

Form

Risk for release into air

Potential routes for Inhalation Exposure

Nanomaterial embedded into a solid matrix or tightly bound to a surface

low

Mechanically working on the material such as cutting, sanding, drilling.

Suspensions

Moderate

Formation of aerosols through agitation such as sonicating, stirring, centrifuging of open containers holding suspensions

Dry powder

High

Any open handling of powder

Once nanomaterials are released into the air, they can remain suspended for days or even weeks. 

Safe Handling

Engineering Controls and Work Practices

Every effort should be made to avoid releasing nanomaterials into the air. Because they can remain suspended for a long time, any release poses a hazard to everybody entering the laboratory.

Perform all work with nanomaterials inside a well-ventilated enclosure such as a chemical fume hood, glove box, biosafety cabinet, or an enclosure made especially for nanomaterial use. Any enclosure that vents into the room must be equipped with a HEPA filter. Develop a procedure for changing the HEPA filter without releasing nanoparticles into the room air.

Some nanomaterials, carbon nanotubes in particular, are difficult to handle in a chemical fume hood because the air flow is often too high to contain the material inside its container. Enclosures specifically made to contain nanomaterials are available. Those enclosures have a lower air flow and are equipped with a mechanism for safe filter change. If possible, dedicate an enclosure for nanomaterial use.

When working with dry powders, sticky floor mats can help reduce the levels of nanomaterials in the air.

Always wet-wipe the area where dry nanomaterials are used. If the wipes are contaminated, collect them in a sealed plastic bag and dispose of them as hazardous waste. A vacuum cleaner with HEPA filter can be used to clean areas that are difficult to wipe.

Personal Protective Equipment

Protect yourself from skin contact by wearing standard laboratory attire such as closed-toe shoes, long pants, a lab coat, safety glasses, and gloves when handling nanomaterials.

A respirator should not be necessary when working in a well-ventilated enclosure. If a respirator is required for certain procedures, remember that other people working in the laboratory who are not wearing respirators are at risk, and nanoparticles may remain in the air after the work is done. Wearing a respirator also requires a medical evaluation and fit-testing before use. Contact Safety and Compliance before purchasing a respirator.

Emergency Procedures

Accidental Exposure

If skin or the eyes are exposed to nanomaterial, rinse with plenty of water.

If nanomaterial is inhaled, move into fresh air. If respiratory irritation or breathing problems persist, seek medical attention.

Spill Procedure

Powdered nanomaterial or debris from mechanically working on embedded nanomaterial should be wiped up with a wet paper towel or a wetted absorbent pad. Spilled suspensions should be wiped up with an absorbent pad compatible with the solvent. Collect contaminated wipes in a sealed plastic bag and dispose of them as hazardous waste.

Storage

Store all nanomaterial in well-sealed containers. Label the container with the chemical identity of the material and add the term “nano.” 

Disposal

Collect nanomaterial in a separate waste stream and dispose of through DRS.

Links and References

Nanotoolkit California Nanosafety Consortium of Higher Education 2012

OSHA Factsheet “Working Safely with Nanomaterials”: 

NIOSH Guide: General Safe Practices for Working with Engineered Nanomaterials in Research Laboratories 

National Nanotechnology Initiative

Last Update: 3/25/2014