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OSMIUM TETROXIDE ICSC: 0528
September 1997
Osmic acid anhydride
Osmium oxide
Osmium tetraoxide
PDF for printing Explanation of fields
CAS No: 20816-12-0
RTECS No: RN1140000
UN No: 2471
EC No: 076-001-00-5
    O4Os
Molecular mass: 254.2

TYPES OF
HAZARD /
EXPOSURE
ACUTE HAZARDS / SYMPTOMS      PREVENTION      FIRST AID / FIRE FIGHTING
FIRE Not combustible but enhances combustion of other substances. NO contact with flammable substances. In case of fire in the surroundings: all extinguishing agents allowed.
EXPLOSION Risk of fire and explosion when mixed with combustible substances.    
 
EXPOSURE   AVOID ALL CONTACT!  
Inhalation Burning sensation. Cough. Headache. Wheezing. Shortness of breath. Visual disturbances. Symptoms may be delayed (see Notes). Local exhaust or breathing protection. Fresh air, rest. Half-upright position. Artificial respiration if indicated. Refer for medical attention.
Skin Redness. Skin burns. Pain. Skin discoloration. Blisters. Protective gloves. Protective clothing. First rinse with plenty of water, then remove contaminated clothes and rinse again. Refer for medical attention.
Eyes Redness. Pain. Blurred vision. Loss of vision. Severe deep burns. Safety goggles, or eye protection in combination with breathing protection if powder. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
Ingestion Abdominal cramps. Burning sensation. Shock or collapse. (See Inhalation). Do not eat, drink, or smoke during work. Wash hands before eating. Rinse mouth. Give nothing to drink. Rest. Refer for medical attention.

SPILLAGE DISPOSAL PACKAGING & LABELLING
Evacuate danger area! Consult an expert! Ventilation. Sweep spilled substance into containers; if appropriate, moisten first to prevent dusting then remove to safe place. Do NOT absorb in saw-dust or other combustible absorbents. Do NOT let this chemical enter the environment (extra personal protection: complete protective clothing including self-contained breathing apparatus). EU classification
T+ Symbol
R: 26/27/28-34
S: (1/2-)7/9-26-45
UN classification
UN Hazard Class: 6.1
UN Pack Group: I

Unbreakable packaging; put breakable packaging into closed unbreakable container. Do not transport with food and feedstuffs. Severe marine pollutant.


EMERGENCY RESPONSE SAFE STORAGE
Transport Emergency Card: TEC (R)-61G64a Separated from combustible and reducing substances, food and feedstuffs. Ventilation along the floor.

IMPORTANT DATA
Physical State; Appearance
COLOURLESS TO PALE YELLOW SOLID IN VARIOUS FORMS, WITH PUNGENT ODOUR.

Chemical dangers
The substance decomposes on heating producing fumes of osmium. The substance is a strong oxidant and reacts with combustible and reducing materials. Reacts with hydrochloric acid to form toxic chlorine gas (see ICSC # 0126). Forms unstable compounds with alkalis.

Occupational exposure limits
TLV (as Os): 0.0002 ppm; 0.0016 mg/m³ (as TWA); 0.0006 ppm; 0.0047 mg/m³ (as STEL) (ACGIH 1997).
MAK: IIb (not established but data is available) (DFG 2006).

Routes of exposure
The substance can be absorbed into the body by inhalation of its vapour, by inhalation of its aerosol and by ingestion.

Inhalation risk
A harmful contamination of the air can be reached very quickly on evaporation of this substance at 20°C..

Effects of short-term exposure
Tear drawing. The substance is corrosive to the eyes, the skin, and the respiratory tract. Inhalation of this substance may cause lung oedema (see Notes). Exposure to high concentrations may result in death. The effects may be delayed. Medical observation is indicated.

Effects of long-term or repeated exposure
Repeated or prolonged contact with skin may cause dermatitis. The substance may have effects on the kidneys.


PHYSICAL PROPERTIES ENVIRONMENTAL DATA
Boiling point: (see Notes) 130°C
Melting point: 42°C
Relative density (water = 1): 4.9
Solubility in water, g/100 ml at 25°C: 6
Vapour pressure, kPa at 27°C: 1.5
Relative vapour density (air = 1): 8.8
This substance may be hazardous to the environment; special attention should be given to crustacea.

NOTES
Begins to sublime and distil well below boiling point.
The symptoms of lung oedema often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation is therefore essential.
Immediate administration of an appropriate spray, by a doctor or a person authorized by him/her, should be considered.
The odour warning when the exposure limit value is exceeded is insufficient.
Do NOT take working clothes home.
Rinse contaminated clothes (fire hazard) with plenty of water.
Card has been partially updated in August 2007: see Occupational Exposure Limits.

IPCS
International
Programme on
Chemical Safety
WHO ILO UNEP EC Prepared in the context of cooperation between the International Programme on Chemical Safety and the European Commission
© IPCS 2006
LEGAL NOTICE Neither the EC nor the IPCS nor any person acting on behalf of the EC or the IPCS is responsible for the use which might be made of this information.

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