International Chemical Safety Cards

METHYL MERCAPTAN ICSC: 0299

METHYL MERCAPTAN
Methanethiol
Mercaptomethane
Methyl sulfhydrate
(cylinder)
CH3SH
Molecular mass: 48.1
CAS # 74-93-1
RTECS # PB4375000
ICSC # 0299
UN # 1064
EC # 016-021-00-3
TYPES OF
HAZARD/
EXPOSURE 		ACUTE HAZARDS/
SYMPTOMS 		PREVENTION FIRST AID/
FIRE FIGHTING
FIRE Extremely flammable.
NO open flames, NO sparks, and NO smoking.
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.
EXPLOSION Gas/air mixtures are explosive.
Closed system, ventilation, explosion-proof electrical equipment and lighting.
In case of fire: keep cylinder cool by spraying with water.
EXPOSURE
STRICT HYGIENE!

  • INHALATION
    		• Cough. Headache. Nausea. Shortness of breath. Sore throat. Unconsciousness.
    		Ventilation, local exhaust, or breathing protection.
    		Fresh air, rest. Half-upright position. Artificial respiration if indicated. Refer for medical attention.
  • SKIN
    		• Redness. Pain. ON CONTACT WITH LIQUID: FROSTBITE.
    		Protective gloves.
    		Remove contaminated clothes. ON FROSTBITE: rinse with plenty of water, do NOT remove clothes. Refer for medical attention.
  • EYES
    		• Redness. Pain.
    		Safety goggles or eye protection in combination with breathing protection.
    		First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
  • INGESTION



    • SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING
    Evacuate danger area! Consult an expert! Ventilation (extra personal protection: self-contained breathing apparatus).
    		Fireproof. Separated from strong oxidants, acids. Cool.

    F symbol
    Xn symbol
    R: 13-20
    S: 16-25
    UN Haz Class: 2.3
    UN Subsidiary Risks: 2.1
    Marine pollutant.
    SEE IMPORTANT INFORMATION ON BACK
    ICSC: 0299 Prepared in the context of cooperation between the IPCS and the Commission of the European Communities © CEC, IPCS, 1993. No modifications to the International version have been made except to add the OSHA PELs, NIOSH RELs and IDLH values.

    International Chemical Safety Cards

    METHYL MERCAPTAN ICSC: 0299

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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 heating and on burning producing toxic sulfur oxides. Reacts violently with strong oxidants. Reacts with acids to form flammable and toxic gas (hydrogen sulfide - see ICSC # 0165).

    OCCUPATIONAL EXPOSURE LIMITS:
     TLV: 0.5 ppm; 0.98 mg/m3 (as TWA) (ACGIH 1992-1993).
    PDK: 0.8 mg/m3 (USSR 1993).
    OSHA PEL: C 10 ppm (20 mg/m3)
    NIOSH REL: C 0.5 ppm (1 mg/m3) 15-minute
    NIOSH IDLH: 150 ppm


    		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 irritates the eyes, the skin and the respiratory tract. Inhalation of this gas may cause lung oedema (see Notes). Rapid evaporation of the liquid may cause frostbite. The substance may cause effects on the central nervous system , resulting in respiratory failure. Exposure at high levels may result in death. Medical observation is indicated.

    EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
    PHYSICAL
    PROPERTIES
    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
    		Relative vapour density (air = 1): 1.7
    Flash point: -18°C
    Explosive limits, vol% in air: 3.9-21.8
    ENVIRONMENTAL
    DATA
    NOTES
    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 are therefore essential. Immediate administration of an appropriate spray, by a doctor or a person authorized by him/her, should be considered. Specific treatment is necessary in case of poisoning with this substance; the appropriate means with instructions must be available. Turn leaking cylinder with the leak up to prevent escape of gas in liquid state.
    Transport Emergency Card: TEC (R)-20G12
    NFPA Code: H 2; F 4; R 0;
    ADDITIONAL INFORMATION


    ICSC: 0299 METHYL MERCAPTAN
    © CEC, IPCS, 1993
    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 IDLH values.