Lab-Specific Procedure

Osmium Tetroxide: Lab-Specific Safety Procedure

08/15/2014 Rev. 0

Department / Bldg. /Lab: PI/Supervisor:
Highly Hazardous Material/ Process Description:

Osmium tetroxide (OsO₄, CAS20816-12-0) is used as a secondary fixative in preparation of biological specimens for electron microscopy.

Hazards:

May be fatal if inhaled, swallowed, or in contact with skin. Acute toxicity is high. Exposure via inhalation, ingestion or skin contact may lead to systemic toxic effects including liver and kidney damage. Exposure to vapor may damage cornea of the eye. This chemical is regarded as a substance with poor warning properties. It is an oxidizing material and may cause fire if in contact with combustible materials.
Potential Health Effects:

Eyes: Severe irritant of the eyes. Exposure to osmium tetroxide vapor can damage the cornea of the eye. Irritation is generally the initial symptom of exposure to low concentrations of osmium tetroxide vapor. May cause sensitization by inhalation or skin contact. Additional symptoms may include lacrimation (tear formation), a gritty feeling in the eyes, temporary clouding of vision, and appearance of rings around lights. Contact with concentrated solutions can cause severe damage and possible blindness.

Skin: Slightly hazardous (permeator). Prolonged contact of the vapor with skin can cause dermatitis. Direct contact with the solid can lead to severe irritation and burns.

Inhalation: Severe irritant of the respiratory tract. Can cause headache, coughing, dizziness, lung damage and difficulty breathing. Severe over-exposure may be fatal.

Ingestion: Extremely hazardous.

Chronic Effects: Toxic to the lungs and nervous system. Repeated or prolonged exposure can produce organ damage. Repeated exposure may produce general deterioration of health by an accumulation in one or many organs.
Designated Work Area:

Handling: Use only within a chemical fume hood. Wear personal protective equipment and avoid exposure to all body parts.

Storage: Pure osmium tetroxide and concentrated solutions should be stored in sealed glass containers (stock solution in a glass bottle with a tight-fitting glass stopper). Plastic containers can be permeated and should not be used as primary storage containers. Glass storage containers should be sealed with parafilm. Containers must be checked at least weekly for blackening of the parafilm, which indicates leakage. Glass containers must be placed in sealed unbreakable secondary container, such as a metal can with a lid. Primary and secondary containers must be labeled with the chemical name and a hazard warning (“Osmium Tetroxide, highly toxic”).

Contact with hydrochloric acid will cause formation of poisonous chlorine gas. Incompatible with strong reducing agents (e.g., reactive metals and metal hydrides), organic materials, powdered metals.

Engineering Controls:

Work is done within a chemical fume hood that is properly functioning (with current inspection). Hood will be cleared of any unnecessary equipment or obstructions to ensure good containment of vapors. A sign will be posted on the hood to notify others that work is in progress.

Work surfaces will be protected with plastic backed absorbent pads to insure containment of spills.

Work areas must be (are) equipped with an eyewash unit and a safety shower.

Unused solutions and waste will be promptly neutralized (see subsequent section).
Administrative Controls:

A written detailed step-by-step protocol must be approved by the lab PI prior to initiating any protocols using this chemical. Changes to the protocol must be documented and approved in writing.

A second person must be present in the lab and aware of the procedure when osmium tetroxide is being used (no working alone).
Personal Protective Equipment:

Eye Protection: Safety goggles (sometimes called “splash goggles”) must be worn during operations – safety glasses are not sufficient.

Hand Protection: Double nitrile gloves must be worn when working with stock solution. Single nitrile gloves may be worn when working with diluted solution (secondary fixative). Change gloves as necessary to ensure proper protection.

Lab Coats: Lab coat (from WHOI service) must be worn. Coat must be buttoned with sleeves rolled down. Chemically-resistant wrist guards may be worn.
Emergency Procedures:

For hazard chemicals spills and other emergencies, dial ext 2911 or 508-289-2911. Personnel exposed to osmium tetroxide should seek immediate medical attention. The safety data sheet (SDS) should go with the person to the emergency room.
First Aid Measures:

Eye Contact: Check for and remove any contact lenses. Rinse eyes immediately with plenty of water keeping eyelids apart and away from eyeballs during irrigation.

Skin Contact: Wash immediately with plenty of water. Gently wash the contaminated area with running water and non-abrasive soap. Be particularly careful to clean folds, crevices and skin creases. Cover irritated skin with an emollient. If irritation persists or is severe, seek immediate medical attention.

Inhalation: Move to fresh air. If breathing is difficult, give oxygen. If victim is not breathing, induce artificial respiration.

Ingestion: Do not induce vomiting. In case of serious injury, damage around the lips and mouth may indicate ingestion. Loosen tight clothing, perform mouth-to-mouth resuscitation if needed. Seek immediate medical attention.
Spills

Preparation:

Kitty litter and corn oil (at least one liter) will be nearby (e.g., in the cabinet next to the fume hood) any time the chemical is being used or stored in the lab.

Incidental Spill (small, low hazard spill):

For small and manageable spills (less than 10 ml),

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  Notify lab PI
  
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  Alert personnel in the immediate area
  
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  Don appropriate PPE (double nitrile gloves, lab coat, goggles)
  
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  Isolate the area to prevent the spread of contamination
  
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  Cover the material with kitty litter soaked in corn oil.
  
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  Scoop the material up into a sealed plastic bag
  
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  Wash the area with an aqueous solution of sodium sulfite or sodium sulfide.
  
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  Clean the area with a detergent solution
  
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  Remove contaminated PPE carefully and place in the bag.
  
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  Treat the bag as hazardous waste.
  

Hazardous Spill (any spill beyond incidental):

Report the emergency by dialing x2911. Attend to any person that has been exposed to the material by implementing first aid measures. Warn others in the area. Evacuate to a safe area.

Waste Disposal:

For safety reasons, solutions will be stabilized prior to disposal. Stabilization will be performed in a chemical fume hood. A 2% solution of osmium tetroxide may be stabilized with twice its volume of corn oil (e.g., 10 ml of 2% osmium tetroxide and 20 ml of corn oil). Corn oil will be poured into the osmium tetroxide solution. Wait for the solution to turn black. More dilute aqueous solutions may be stabilized by adding sodium sulfite or sodium sulfide to reduce the osmium tetroxide to less hazardous forms. To test for stabilization, hold a piece of filter paper soaked in corn oil over the container. If the filter paper turns black, vapors still contain osmium tetroxide and more corn oil is needed.

All labware that has contacted osmium tetroxide must be stabilized by dipping in corn oil or an aqueous solution of sodium sulfite or sodium sulfide before removing from the hood.
Excess osmium tetroxide and all waste material contain osmium tetroxide must be stabilized and placed in a suitable container which is stored in an SAA with the appropriate label and disposed of as hazardous waste through EH&S.

Acknowledgement:

PI/Supervisors are responsible for providing lab specific training, reviewing emergency procedures with lab personnel, and implementing safe lab practices and engineering controls. PI/Supervisors and lab personnel must sign below acknowledging that they have reviewed and understand this SOP.

Name	Signature	Date

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