Temephos

  • O,O’-(Thiodi-4,1-phenylene)phosphorothioic acid, O,O,O’,O’-tetramethyl ester
  • O,O,O',O'-Tetramethyl O,O'-thiodi-p-phenylene bis(phosphorothioate)
  • Phosphorothioic acid, o,O'-(thiodi-4,1-phenylene) o,O,O',O'tetramethyl ester
Formula
C16H20O6P2S3
Structure
Description
White crystalline solid or liquid. Technical grade is a viscous brown liquid.
Uses
Larvicide for mosquitoes, black flies & midges & in other applications.

Registry Numbers and Inventories.
CAS
3383-96-8
EC (EINECS/ELINCS)
222-191-1
RTECS
TF6890000
RTECS class
Agricultural Chemical and Pesticide; Reproductive Effector; Primary Irritant
UN (DOT)
2783
Merck
12,9286
Beilstein/Gmelin
1896901
EPA OPP
59001
Swiss Giftliste 1
G-2981
Canada DSL/NDSL
NDSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C16H20O6P2S3
Formula mass
466.48
Melting point, °C
30.6
Vapor pressure, mmHg
9E-10
Density
1.32 g/cm3 (20 C)
Solubility in water
insoulble

Hazards and Protection.
Storage
Store in cool, dry, well ventilated, secure area out of reach children and animals.
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Wear appropriate protective gloves, clothing and goggles.
Respirators
Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks
Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS.
Stability
Stable indefinitely at room temperature; no observed hydrolysis at pH 8 at room temperature for several wk or at pH 11 at 40 C for several hr. Optimum stability at pH 5-7 stable @ 25 C and in natural fresh and saline waters.
Incompatibilities
Incompatible with alkaline substances.
Decomposition
When heated to decomposition it emits toxic phosphorus oxides and sulfur oxides fumes.

Fire.
Flash Point,°C
43-93 (closed cup)
Fire fighting
Dry chemicals, carbon dioxide for small fires. Water spray, foam for large fires.
Fire potential
Combustible material: may burn but does not ignite readily.
Hazards
Containers may explode when heated.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.

Health.
Exposure limit(s)
TLV: ppm; 10 mg/m3 (ACGIH 1994-1995). OSHA PEL: TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) NIOSH REL: TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)
Poison_Class
4
Exposure effects
Reduced body temperature or elevated body temperature may occur. Low heart rate and abnormally low blood pressure may develop after moderate to severe poisoning. Rapid heart rate, elevated blood pressure, and changes in respiratory rate may also occur. Early giddiness, anxiety headache, and restlessness followed by ataxia, drowsiness, and confusion are common with moderate to severe exposures. Sporadic reports of human birth defects related to organophosphates have not been fully verified.
   Ingestion
Nausea, vomiting, abdominal cramps, and diarrhea are common muscarinic effects. Both painless and frank clinical pancreatitis have been reported.
   Inhalation
Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Effects of contact or inhalation may be delayed.
   Skin
Profuse sweating is common. Pallor may be noted. Dermal sensitization has been reported.
   Eyes
Constriction of the pupil, tearing, and blurred vision are common. Prolonged dialation of the pupils may occur. Salivation commonly occurs.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult.
   Skin
Remove and isolate contaminated clothing and shoes. Immediately flush with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin.
   Eyes
Immediately flush with running water for at least 20 minutes.

Transport.
UN number
2783
Response guide
Hazard class
6.1
Packing Group
I; II; III