Si
Atomic mass: 28.09
ICSC # 1508
CAS # 7440-21-3
RTECS # VW0400000
UN # 1346
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Types of Hazard/ Exposure
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Acute Hazards/ Symptoms
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Prevention
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First Aid/
Fire Fighting
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FIRE
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Combustible under specific conditions.
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NO open flames.
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Special powder,
dry sand,
NO hydrous agents.
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Explosion
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Finely dispersed particles form explosive mixtures in air.
Risk of fire and explosion on contact with halogens oxidants.
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Prevent deposition of dust; closed system, dust explosion-proof electrical equipment and lighting.
Prevent build-up of electrostatic charges (e.g., by grounding).
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Exposure
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•Inhalation
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Cough.
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Local exhaust or breathing protection.
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Fresh air, rest.
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•Skin
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Redness.
Roughness.
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Protective gloves.
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Rinse skin with plenty of water or shower.
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•Eyes
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Redness.
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Safety goggles.
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First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
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•Ingestion
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Do not eat, drink, or smoke during work.
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Rinse mouth.
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Spillage Disposal
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Storage
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Packaging & Labelling
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Sweep spilled substance into containers; if appropriate, moisten first to prevent dusting.
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Separated from
incompatible materials
.
See Chemical Dangers.
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UN Hazard Class: 4.1
UN Packing Group: III
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Important Data
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Physical State; Appearance:
STEEL-GREY CRYSTALS
OR
BLACK
TO BROWN
AMORPHOUS POWDER
Physical Dangers:
Dust explosion possible if in powder or granular form, mixed with air.
If dry, it can be charged electrostatically by swirling, pneumatic transport, pouring, etc.
Chemical Dangers:
Reacts
violently with
oxidants
,
halogens
, metal carbonates and metal acetylides
causing fire hazard.
Reacts
violently with
metal hexafluorides
causing fire and explosion hazard.
Reacts
on heating
with
water
forming flammable/explosive gas (hydrogen - see ICSC0001)
.
Occupational Exposure Limits:
TLV not established.
MAK not established.
OSHA PEL: TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)
NIOSH REL: TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)
NIOSH IDLH: N.D. See: IDLH INDEX
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Routes of Exposure:
The substance can be absorbed into the body
by inhalation.
Inhalation Risk:
A nuisance-causing concentration of airborne particles can be reached quickly when dispersed.
Effects of Short-Term Exposure:
May cause mechanical irritation.
to
the eyes
and
the respiratory tract.
Effects of Long-Term or Repeated Exposure:
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Physical
Properties
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Boiling point: 2355°C
Melting point: 1410°C
Density: 2.33
g/cm3
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Solubility in water: none
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Environmental
Data
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N O T E S
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Reacts violently with fire extinguishing agents such as water.
Transport Emergency Card: TEC (R)-41GF3-II+III
Card has been partially updated in February 2009: see Occupational Exposure Limits.
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ADDITIONAL INFORMATION
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ICSC: 1508
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SILICON
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(C) IPCS, CEC, 1994
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IMPORTANT LEGAL NOTICE:
Neither NIOSH, the CEC or the IPCS nor any person acting on behalf of NIOSH,
the CEC or the IPCS is responsible for the use which might be made of this
information. This card contains the collective views of the IPCS Peer Review Committee and may
not reflect in all cases all the detailed requirements included in national legislation
on the subject. The user should verify compliance of the cards with the relevant legislation
in the country of use.
The only modifications made to produce the U.S. version is inclusion of the OSHA PELs, NIOSH RELs and NIOSH IDLH values.
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