Chemical Datasheet
OSMIUM TETROXIDE |
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Chemical Identifiers
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| CAS Number | UN/NA Number | DOT Hazard Label | USCG CHRIS Code |
|---|---|---|---|
|
|
none | |
| NIOSH Pocket Guide | International Chem Safety Card | ||
Osmium tetroxide
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NFPA 704
data unavailable
General Description
A colorless or yellow solid with a pungent odor of chlorine. Begins to sublime below melting point. Soluble in alcohol. Toxic by inhalation and a strong irritant to the eyes and mucous membranes.
Hazards
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The
Hazard fields
include
special hazard alerts
air and water
reactions, fire hazards, health hazards, a reactivity profile, and
details about
reactive groups assignments
and
potentially incompatible absorbents.
The information in CAMEO Chemicals comes from a variety of
data sources.
Reactivity Alerts
- Strong Oxidizing Agent
Air & Water Reactions
Soluble in water.
Fire Hazard
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion or sodium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2024)
Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Corrosives in contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, ERG Guide 147 (lithium ion or sodium ion batteries) or ERG Guide 138 (sodium batteries) should also be consulted. (ERG, 2024)
Health Hazard
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination. (ERG, 2024)
TOXIC and/or CORROSIVE; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause environmental contamination. (ERG, 2024)
Reactivity Profile
OSMIUM TETROXIDE is incompatible with hydrochloric acid and easily oxidizes organic materials. Contact with other materials may cause fire. (NIOSH, 2024). Reacts explosively with 1-methylimidazole [J. Chem. Soc., Dalton Trans., 1979, 1084].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents
Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below. More info about absorbents, including situations to watch out for...
- Cellulose-Based Absorbents
- Expanded Polymeric Absorbents
Response Recommendations
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Response Recommendation fields
include isolation and evacuation distances, as well as recommendations for
firefighting, non-fire response, protective clothing, and first aid. The
information in CAMEO Chemicals comes from a variety of
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Isolation and Evacuation
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.
SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.
FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)
IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.
SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.
FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)
Firefighting
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
SMALL FIRE: Dry chemical, CO2 or water spray.
LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.
FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)
SMALL FIRE: Dry chemical, CO2 or water spray.
LARGE FIRE: Dry chemical, CO2, alcohol-resistant foam or water spray. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.
FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)
Non-Fire Response
Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2024)
ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. (ERG, 2024)
Protective Clothing
Excerpt from NIOSH Pocket Guide for Osmium tetroxide:
Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.
Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.
Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.
Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.
Change: DAILY - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.
Provide: EYEWASH - Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substances; this is irrespective of the recommendation involving the wearing of eye protection. (NIOSH, 2024)
:Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.
Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.
Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.
Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.
Change: DAILY - Workers whose clothing may have become contaminated should change into uncontaminated clothing before leaving the work premises.
Provide: EYEWASH - Eyewash fountains should be provided in areas where there is any possibility that workers could be exposed to the substances; this is irrespective of the recommendation involving the wearing of eye protection. (NIOSH, 2024)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
Excerpt from NIOSH Pocket Guide for Osmium tetroxide:
Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.
Skin: SOAP WASH IMMEDIATELY - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly.
Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.
Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)
:Eye: IRRIGATE IMMEDIATELY - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.
Skin: SOAP WASH IMMEDIATELY - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly.
Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.
Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)
Physical Properties
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Physical Property fields
include properties such as vapor pressure and
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toxic exposure thresholds
The information in CAMEO Chemicals comes from a variety of
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Note: For Vapor Density and Specific Gravity, comparing the value to 1.0 can tell you if the chemical will likely sink/rise in air or sink/float in fresh water (respectively). Short phrases have been added to those values below as an aid. However, make sure to also consider the circumstances of a release. The Vapor Density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a Vapor Density value less than 1). Also, the Specific Gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water.
Note: For Vapor Density and Specific Gravity, comparing the value to 1.0 can tell you if the chemical will likely sink/rise in air or sink/float in fresh water (respectively). Short phrases have been added to those values below as an aid. However, make sure to also consider the circumstances of a release. The Vapor Density comparisons are only valid when the gas escaping is at the same temperature as the surrounding air itself. If the chemical is escaping from a container where it was pressurized or refrigerated, it may first escape and behave as a heavy gas and sink in the air (even if it has a Vapor Density value less than 1). Also, the Specific Gravity comparisons are for fresh water (density 1.0 g/mL). If your spill is in salt water (density about 1.027 g/mL), you need to adjust the point of comparison. There are some chemicals that will sink in fresh water and float in salt water.
| Chemical Formula: |
|
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: data unavailable
Melting Point:
105°F
(NIOSH, 2024)
Vapor Pressure:
7 mmHg
(NIOSH, 2024)
Vapor Density (Relative to Air): data unavailable
Specific Gravity:
5.1
(NIOSH, 2024)
- Denser than water; will sink
Boiling Point:
266°F
at 760 mmHg
(NIOSH, 2024)
Molecular Weight:
254.2
(NIOSH, 2024)
Water Solubility:
6 %
at 77°F
(NIOSH, 2024)
Ionization Energy/Potential:
12.60 eV
(NIOSH, 2024)
IDLH:
1 mg/m3
(NIOSH, 2024)
AEGLs (Acute Exposure Guideline Levels)
| Exposure Period | AEGL-1 | AEGL-2 | AEGL-3 |
|---|---|---|---|
| 10 minutes | NR | 0.015 ppm | 5 ppm |
| 30 minutes | NR | 0.011 ppm | 5 ppm |
| 60 minutes | NR | 0.0084 ppm | 4 ppm |
| 4 hours | NR | 0.0033 ppm | 2.5 ppm |
| 8 hours | NR | 0.0017 ppm | 2 ppm |
NR = Not recommended due to insufficient data.
(NAC/NRC, 2024)
ERPGs (Emergency Response Planning Guidelines)
No ERPG information available.PACs (Protective Action Criteria)
| Chemical | PAC-1 | PAC-2 | PAC-3 |
|---|---|---|---|
| Osmium tetroxide (20816-12-0) | 0.0006 ppm | 0.0084 ppm | 4 ppm |
(DOE, 2024)
Regulatory Information
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The
Regulatory Information fields
include information from
the U.S. Environmental Protection Agency's Title III Consolidated List of
Lists,
the U.S. Cybersecurity and Infrastructure Security Agency's Chemical Facility
Anti-Terrorism Standards,
and the U.S. Occupational Safety and Health Administration's
Process Safety Management of Highly Hazardous Chemicals Standard List
(see more about these
data sources).
EPA Consolidated List of Lists
| Regulatory Name | CAS Number/ 313 Category Code |
EPCRA 302 EHS TPQ |
EPCRA 304 EHS RQ |
CERCLA RQ | EPCRA 313 TRI |
RCRA Code |
CAA 112(r) RMP TQ |
|---|---|---|---|---|---|---|---|
| Osmium oxide OsO4 (T-4)- | 20816-12-0 | 1000 pounds | X | P087 | |||
| Osmium tetroxide | 20816-12-0 | 1000 pounds | 313 | P087 |
- "X" indicates that this is a second name for an EPCRA section 313 chemical already included on this consolidated list. May also indicate that the same chemical with the same CAS number appears on another list with a different chemical name.
(EPA List of Lists, 2024)
CISA Chemical Facility Anti-Terrorism Standards (CFATS)
No regulatory information available.OSHA Process Safety Management (PSM) Standard List
| Chemical Name | CAS Number | Threshold Quantity (TQ) |
|---|---|---|
| Osmium Tetroxide | 20816-12-0 | 100 pounds |
(OSHA, 2019)
Alternate Chemical Names
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This section provides a listing of alternate names for this chemical,
including trade names and synonyms.
- MILAS' REAGENT
- OSMIC ACID ANHYDRIDE
- OSMIUM OXIDE
- OSMIUM OXIDE (OSO4)
- OSMIUM OXIDE OSO4 (T-4)-
- OSMIUM TETRAOXIDE
- OSMIUM TETROXIDE
- OSMIUM(IV) OXIDE
- REAGENTS, MILAS'
- TETRAOXOOSMIUM
Web site owner:
Office of Response and Restoration,
National Ocean Service,
National Oceanic and Atmospheric Administration.
USA.gov.
CAMEO Chemicals version 3.1.0 rev 2.