ICSC 0299 - METHYL MERCAPTAN

METHYL MERCAPTAN	ICSC: 0299 (June 2003)
Methanethiol Mercaptomethane Methyl sulfhydrate Thiomethanol

CAS #: 74-93-1

UN #: 1064

EC Number: 200-822-1

	ACUTE HAZARDS	PREVENTION	FIRE FIGHTING
FIRE & EXPLOSION	Extremely flammable. Gas/air mixtures are explosive.	NO open flames, NO sparks and NO smoking. Closed system, ventilation, explosion-proof electrical equipment and lighting.	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. In case of fire: keep cylinder cool by spraying with water.

STRICT HYGIENE!
	SYMPTOMS	PREVENTION	FIRST AID
Inhalation	Cough. Sore throat. Dizziness. Headache. Nausea. Vomiting. Unconsciousness.	Use ventilation, local exhaust or breathing protection.	Fresh air, rest. Artificial respiration may be needed. Refer for medical attention.
Skin	ON CONTACT WITH LIQUID: FROSTBITE.	Cold-insulating gloves.	Remove contaminated clothes. Refer for medical attention . ON FROSTBITE: rinse with plenty of water, do NOT remove clothes.
Eyes	Redness. Pain.	Wear 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 refer for medical attention.
Ingestion

SPILLAGE DISPOSAL	CLASSIFICATION & LABELLING
Evacuate danger area! Consult an expert! Personal protection: self-contained breathing apparatus. Ventilation. Do NOT let this chemical enter the environment.	According to UN GHS Criteria Transportation UN Classification UN Hazard Class: 2.3; UN Subsidiary Risks: 2.1
STORAGE
Fireproof. Separated from strong oxidants and acids. Cool. Store in an area without drain or sewer access.
PACKAGING
Marine pollutant.

METHYL MERCAPTAN

ICSC: 0299

PHYSICAL & CHEMICAL INFORMATION
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 Decomposes on burning. This produces toxic fumes including sulfur oxides and hydrogen sulfide. Reacts violently with strong oxidants. Reacts with water, steam and acids. This produces flammable and toxic gas.	Formula: CH₃SH Molecular mass: 48.1 Boiling point: 6°C Melting point: -123°C Relative density (water = 1): 0.9 Solubility in water, g/100ml at 20°C: 2.3 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

PHYSICAL & CHEMICAL INFORMATION

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
Decomposes on burning. This produces toxic fumes including sulfur oxides and hydrogen sulfide. Reacts violently with strong oxidants. Reacts with water, steam and acids. This produces flammable and toxic gas.

Formula: CH₃SH
Molecular mass: 48.1
Boiling point: 6°C
Melting point: -123°C
Relative density (water = 1): 0.9
Solubility in water, g/100ml at 20°C: 2.3
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

EXPOSURE & HEALTH EFFECTS
Routes of exposure The substance can be absorbed into the body by inhalation. Effects of short-term exposure The substance is irritating to the eyes and respiratory tract. The substance may cause effects on the central nervous system. This may result in respiratory depression. Exposure at high levels could cause unconsciousness. Exposure at high levels could cause death. The effects may be delayed. Medical observation is indicated.	Inhalation risk A harmful concentration of this gas in the air will be reached very quickly on loss of containment. Effects of long-term or repeated exposure

EXPOSURE & HEALTH EFFECTS

Routes of exposure
The substance can be absorbed into the body by inhalation.

Effects of short-term exposure
The substance is irritating to the eyes and respiratory tract. The substance may cause effects on the central nervous system. This may result in respiratory depression. Exposure at high levels could cause unconsciousness. Exposure at high levels could cause death. The effects may be delayed. Medical observation is indicated.

Inhalation risk
A harmful concentration of this gas in the air will be reached very quickly on loss of containment.

Effects of long-term or repeated exposure

OCCUPATIONAL EXPOSURE LIMITS
TLV: 0.5 ppm as TWA. MAK: 1.0 mg/m³, 0.5 ppm; peak limitation category: II(2); pregnancy risk group: D

ENVIRONMENT
The substance is very toxic to aquatic organisms. It is strongly advised not to let the chemical enter into the environment.

NOTES
Turn leaking cylinder with the leak up to prevent escape of gas in liquid state.

ADDITIONAL INFORMATION

EC Classification
Symbol: F+, T, N; R: 12-23-50/53; S: (2)-16-25-60-61

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    See Also:
       Toxicological Abbreviations
       METHYL MERCAPTAN (JECFA Evaluation)