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NIOSH

METHYL MERCAPTAN

ICSC: 0299

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
June 05, 2003 Validated

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. Sore throat. Dizziness. Headache. Nausea. Vomiting. Unconsciousness.
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.
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. Do NOT let this chemical enter the environment. Personal protection: self-contained breathing apparatus.
Fireproof. Separated from strong oxidants, acids. Cool. Store in an area without drain or sewer access.

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
ICSC: 0299 Prepared in the context of cooperation between the International Programme on Chemical Safety & the Commission of the European Communities (C) IPCS CEC 1994. No modifications to the International version have been made except to add the OSHA PELs, NIOSH RELs and NIOSH IDLH values.

METHYL MERCAPTAN

ICSC: 0299

I

M

P

O

R

T

A

N

T


D

A

T

A

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


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:

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
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

ENVIRONMENTAL
DATA

The substance is very toxic to aquatic organisms. It is strongly advised that this substance does not enter the environment.

N O T E S

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.

ADDITIONAL INFORMATION



ICSC: 0299 METHYL MERCAPTAN
(C) IPCS, CEC, 1994
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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