NIOSH Pocket Guide to Chemical Hazards

Methyl demeton

CAS 8022-00-2


RTECS TG1760000
Synonyms & Trade Names
Demeton methyl; O,O-Dimethyl 2-ethylmercaptoethyl thiophosphate; Metasystox®; Methyl mercaptophos; Methyl systox®
DOT ID & Guide


NIOSH REL: TWA 0.5 mg/m3 [skin]
OSHA PEL†: none
IDLH N.D. See: IDLH INDEX Conversion
Physical Description
Oily, colorless to pale-yellow liquid with an unpleasant odor. [insecticide] [Note: Technical grade consists of 2 isomers: thiono & thiolo.]
MW: 230.3
BP: Decomposes
FRZ: ?
Sol: 0.03-0.3%
VP: 0.0004 mmHg
IP: ?

Sp.Gr: 1.20
Fl.P: ?
UEL: ?
LEL: ?

Combustible Liquid
Incompatibilities & Reactivities
Strong oxidizers, alkalis, water
Measurement Methods
None available
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated
Remove: When wet or contaminated
Change: Daily
Provide: Eyewash, Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap wash immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Important additional information about respirator selection
Respirator Recommendations Not available.
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Irritation eyes, skin; ache eyes, rhinorrhea (discharge of thin mucus); nausea, headache, dizziness, vomiting
Target Organs Eyes, skin, respiratory system, central nervous system, cardiovascular system, blood cholinesterase
See also: INTRODUCTION   See ICSC CARD: 0862