Methanethiol
Mercaptomethane
Methyl sulfhydrate
Thiomethanol
CH3SH
Molecular mass: 48.1
(cylinder)
ICSC # 0299
CAS # 74-93-1
RTECS # PB4375000
UN # 1064
EC # 016-021-00-3
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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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Extremely flammable.
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NO open flames, NO sparks, and NO smoking.
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Shut off supply; if not possible and no risk to surroundings, let the fire burn itself out; in other cases extinguish with powder, carbon dioxide.
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Explosion
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Gas/air mixtures are explosive.
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Closed system, ventilation, explosion-proof electrical equipment and lighting.
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In case of fire: keep cylinder cool by spraying with water.
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Exposure
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STRICT HYGIENE!
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•Inhalation
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Cough.
Sore throat.
Dizziness.
Headache.
Nausea.
Vomiting.
Unconsciousness.
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Ventilation, local exhaust, or breathing protection.
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Fresh air, rest.
Artificial respiration may be needed.
Refer for medical attention.
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•Skin
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ON CONTACT WITH LIQUID: FROSTBITE.
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Cold-insulating gloves.
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Remove contaminated clothes.
Refer for medical attention.
ON FROSTBITE: rinse with plenty of water, do NOT remove clothes.
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•Eyes
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Redness.
Pain.
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Safety goggles,
or eye protection in combination with breathing protection.
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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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Spillage Disposal
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Storage
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Packaging & Labelling
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Evacuate danger area!
Consult an expert!
Ventilation.
Do NOT let this chemical enter the environment.
Personal protection: self-contained breathing apparatus.
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Fireproof.
Separated from
strong oxidants,
acids.
Cool.
Store in an area without drain or sewer access.
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Marine pollutant.
F+ symbol
T symbol
N symbol
R: 12-23-50/53
S: 2-16-25-60-61
UN Hazard Class: 2.3
UN Subsidiary Risks: 2.1
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Important Data
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Physical State; Appearance:
COLOURLESS
GAS
, WITH CHARACTERISTIC ODOUR.
Physical Dangers:
The gas is heavier than air
and may travel along the ground; distant ignition possible.
Chemical Dangers:
The substance decomposes
on burning
producing
toxic fumes
including
sulfur oxides
and
hydrogen sulfide
.
Reacts violently with strong oxidants.
Reacts
with
water
,
steam or
acids
to form flammable and toxic gas.
Occupational Exposure Limits:
TLV: 0.5 ppm as TWA; (ACGIH 2004).
MAK: 0.5 ppm, 1.0 mg/m3
Peak limitation category: II(2); Pregnancy risk group: D;
(DFG 2006).
OSHA PEL: C 10 ppm (20 mg/m3)
NIOSH REL: C 0.5 ppm (1 mg/m3) 15-minute
NIOSH IDLH: 150 ppm See: 74931
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Routes of Exposure:
The substance can be absorbed into the body
by inhalation.
Inhalation Risk:
A harmful concentration of this gas in the air will be reached very quickly on loss of containment.
Effects of Short-Term Exposure:
The substance
is irritating to
the eyes
and
the respiratory tract
.
The substance may cause effects on the
central nervous system
, resulting in respiratory depression.
Exposure at high levels may result in unconsciousness.
Exposure at high levels may result in death.
The effects may be delayed.
Medical observation is indicated.
Effects of Long-Term or Repeated Exposure:
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Physical
Properties
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Boiling point: 6°C
Melting point: -123°C
Relative density (water = 1): 0.9
Solubility in water, g/100 ml at 20°C: 2.3
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Vapour pressure, kPa at 26.1°C: 202
Relative vapour density (air = 1): 1.66
Flash point: Flammable Gas
Explosive limits, vol% in air: 3.9-21.8
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Environmental
Data
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The substance is very toxic to aquatic organisms.
It is strongly advised that this substance does not enter the environment.
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N O T E S
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Turn leaking cylinder with the leak up to prevent escape of gas in liquid state.
Card has been partly updated in October 2004. See sections Occupational Exposure Limits, EU classification, Emergency Response.
Transport Emergency Card: TEC (R)-20G2TF
NFPA Code: H 4; F 4; R 0;
Card has been partially updated in July 2007: see Occupational Exposure Limits.
Card has been partially updated in January 2008: see Storage.
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ADDITIONAL INFORMATION
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ICSC: 0299
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METHYL MERCAPTAN
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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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