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Working Safely with Engineered Nanomaterials

Safety Orientation Checklist-Working Safely with Engineered Nanostructures

Scope and Applicability

This procedure applies to the procurement, generation, distribution (sharing), use, shipping, and disposal of engineered nanomaterials at NC State University.

Definition

 Engineered nanomaterials - Carbon nanotubes, carbon nanowires, carbon fullerenes, nanodots and any other material which has structured components with at least one dimension less than 100 nanometer, including carbon containing materials and other materials of differing elemental composition.  These materials may be part of a liquid suspension or may be individual particles or fibers. This definition does not apply to engineered nanomaterials incorporated into a finished manufactured product, nor applies to ultrafine particles which occur in this size but are generated as products of combustion such welding fume or diesel exhaust.

Abstract

 This standard operating procedure, when used in conjunction with completion of a brief hazard awareness module, should provide employees and students with an adequate “hazard communication” basis for use of engineered nanomaterials at NC State.

Standard Operating Procedure 

Obtaining / Growing / Generating / Sharing Engineered Nanomaterials

  1. Purchase / Growth / Generation– Persons purchasing, growing, or otherwise generating engineered nanomaterials in their laboratories must include these materials on their chemical inventories and note their presence on the target chemical checklist within their written safety plan. Prior to use, the single page hazard awareness sheet must be reviewed and hazard awareness training completed. See Section 4.2  You should keep good records describing these materials as a number of parameters may influence material behavior and toxicity*1
  2. Distribution / Sharing – When transferring or sharing engineered nanomaterials with other research staff within the University, the single page hazard awareness page must be presented with the material. Persons receiving engineered nanomaterials must include these materials on their chemical inventories and note their presence on the target chemical checklist within their written safety plan and complete the hazard awareness training.
  3. Shipping – Shipments of engineered nanomaterials must be approved by EH&S, who will provide details on labeling, packaging, and any appropriate hazard awareness information to be provided along with the material.

Hazard Awareness Training

  1. Prior to use of engineered nanomaterials, complete a brief Safety Orientation Checklist-Working Safely with Engineered Nanostructures . This module includes a review of this standard operating procedure and a short safety awareness PowerPoint presentation.
  2. Provide a copy of the Safety Orientation Checklist-Working Safely with Engineered Nanostructures requirements page to any person with whom you share engineered nanomaterials
  3. Review MSDS for material in use, but note shortcoming of some MSDS for engineered nanomaterials.*1

 Engineering Controls

  1. Exhausted enclosures are required for handling of engineered nanomaterial powders or fibers.
  2. Furnaces must be connected to local exhaust ventilation. 
  3. Where large quantities are utilized, filtration of exhaust may be necessary. Contact Environmental Health and Safety for additional information.

Work Practices

  1. Wet wipe work surfaces, such as benchtops where EM particles, fibers, or solutions have been handled, the end of each day.
  2. Wash hands with soap and water prior to leaving lab.

Storage

  1. Label all nanomaterial containers clearly with both name and composition, such as “cadmium selenide nanodots”.

Waste Disposal

  1. Dispose of both the engineered nanomaterial and any materials used for wipe up of work surfaces or wipe down of generation equipment with name of the material preceded by words “nanosize” such as “nanosize cadmium selenide contaminated waste unless “nano is contained in the name, such as “cadmium selenide nanodots”.

Protective Equipment

  1. Use nitrile gloves for handling dry materials. When nanomaterials are present in a solvent carrier glove selection should be based on the suitability of the glove for protection against the particular solvent.  Where appropriate glove protection for the carrier solvent is not clear, a combination of high dexterity outer glove (e.g 4 mil nitrile) combined with a laminated inner glove (e.g SilverShield) is recommended.  
  2. Utilize respiratory protection where airborne exposure to engineered nanomaterials is expected (e.g. cleanout of systems used for growth of carbon nanotubes.). Contact NC State Environmental Health and Safety Department for assistance with respirator selection as far in advance of need to wear as possible. 

Spills

  1. Absorb liquid suspensions with absorbent pad.  Follow with a wet wipe with an absorbent towelette.  Dispose of materials used for wipe up with name of material preceded by words “nanosized” such as “nanosized cadmium selenide contaminated waste”.
  2. Do not dry sweep. Wet wipe dry materials with an absorbent towelette.  Wipe with multiple passes to collect materials. Label and dispose of materials as noted above.
  3. Larger spills of dry material may also be picked up with a HEPA filtered vacuum, but only after such vacuum has been leak checked to insure its integrity.   A wet wiping will need to follow dry pickup such as vacuuming.  Wet wipe methods are preferable to HEPA vacuuming for small spills.
  4. NC State EH&S should be notified prior to use of materials where system cleanout or pickup of spills with HEPA vacuum would be anticipated so that proper procedures can be reviewed.

If Exposed

  1. Skin *3 – wash with soap and water .  If in solution, follow standard fire aid procedures for eye and skin contact which involves use of eyewash and shower for corrosive materials.
  2. Inhalation *3– Contact Environmental Health and Safety with concerns about inhalation. (pre-use or period medical tests or examinations of persons working with engineered nanomaterials on a laboratory scale is presently not considered necessary)
  3. Ingestion – Contact 911 to reach Campus Police who can provide contact to University emergency medical personnel.

Air Sampling

  1. Air sampling may be conducted for verification of adequacy of engineering controls.
  2. Air sampling may also be conducted upon request of the lab supervisor or employee if concerned about potential airborne exposure.
  3. In some cases, air sampling may be helpful for characterization of engineered nanomaterials, useful both for further research and also as the basis for future toxicological and epidemiological studies. EH&S can be contacted for assistance. *1

Foot Notes

*1 “The physical and chemical characterization of NM (nanomaterials) are important steps in toxicological and ecotoxicological studies in order to correctly evaluate and assess their potential exposure routes, toxicity, and related risk.” (Nanotoxicity, Monteiro-Riviere and Tran, 2007, p.19)  Records of research use will ideally include the size, shape, surface area, chemical composition, lattice structure, surface chemistry, surface charge, and aggregation state, as well as the makeup of any associated liquid media if supplied as suspension. 
*2  MSDS for many engineered nanomaterials do not recognize the potential for differences in material behavioral or toxicological properties as particle size decreases.  “It is well established …that nanomaterials display properties and behavior that can be very different compared to the corresponding bulk materials of the same chemical composition.” (Nanotoxicity, Monteiro-Riviere and Tran, 2007, p.19)

*3   Skin Contact – Some studies suggest that nanoparticles also could enter the body through the skin during occupational exposure.  At this time, it is not known if skin penetration of nanoparticles would result in adverse effects, as these studies have not been reported in animal models 
      Inhalation – Experimental studies in rats have shown that at equivalent mass doses, insoluble ultrafine particles are more potent than larger particles of similar composition in causing pulmonary inflammation, tissue damage, and lung tumors.  Discrete nanoparticles (35-37 nm count median diameter) that deposit in the nasal region may be able to enter the brain by translocation along the olfactory nerve, as was recently observed in rats.
      Ingestion – Little is known about possible adverse effects from the ingestion of nanoparticles.  It should be noted that particles are swallowed after inhalation if deposited in the nose, throat, and upper airways through the body’s clearance mechanism.