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NIOSH

DIMETHYL HYDROGEN PHOSPHITE

ICSC: 1599

Dimethylphosphite
Dimethyl hydrogen phosphonate
Phosphorous acid dimethyl ester
Dimethylphosphonate
C2H7O3P
Molecular mass: 110.1
ICSC # 1599 		CAS # 868-85-9
RTECS # SZ7710000
October 20, 2005 Validated

TYPES OF HAZARD/ EXPOSURE

ACUTE HAZARDS/ SYMPTOMS

PREVENTION

FIRST AID/
FIRE FIGHTING

FIRE Combustible.
NO open flames, NO sparks, and NO smoking.
Foam. Alcohol-resistant foam. Carbon dioxide.
EXPLOSION Above 70°C explosive vapour/air mixtures may be formed.
Above 70°C use a closed system, ventilation.
In case of fire: cool drums, etc., by spraying with water but avoid contact of the substance with water. Combat fire from a sheltered position.
EXPOSURE


•INHALATION Cough. Nausea. Sore throat.
Ventilation, local exhaust, or breathing protection.
Fresh air, rest. Refer for medical attention.
•SKIN MAY BE ABSORBED! Redness. Pain.
Protective clothing. Protective gloves.
First rinse with plenty of water, then remove contaminated clothes and rinse again.
•EYES Redness. Pain.
Safety goggles .
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
•INGESTION Diarrhoea. Nausea. Vomiting.
Do not eat, drink, or smoke during work.
Rinse mouth. Do NOT induce vomiting. Refer for medical attention.

SPILLAGE DISPOSAL

STORAGE

PACKAGING & LABELLING

Personal protection: filter respirator for acid gases. Chemical protection suit. Do NOT let this chemical enter the environment. Cover the spilled material with absorbent. Collect leaking liquid in sealable containers.
Dry. Store in an area without drain or sewer access. Separated from food and feedstuffs . See Chemical Dangers.

ICSC: 1599 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.

DIMETHYL HYDROGEN PHOSPHITE

ICSC: 1599

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PHYSICAL STATE; APPEARANCE:
COLOURLESS LIQUID

PHYSICAL DANGERS:
The vapour is heavier than air.

CHEMICAL DANGERS:
The substance decomposes rapidly on heating producing toxic fumes including phosphorus oxides and phosphine ; on contact with moist air above 220°C producing phosphoric acid and methanol . The solution in water is a strong acid, it reacts violently with bases and is corrosive. Reacts violently with acids and oxidants .

OCCUPATIONAL EXPOSURE LIMITS:
TLV not established.
MAK:
Carcinogen category: 3B;
(DFG 2005).


ROUTES OF EXPOSURE:
The substance can be absorbed into the body by inhalation, through the skin and by ingestion.

INHALATION RISK:
A harmful contamination of the air will be reached slowly on evaporation of this substance at 20°C; on spraying or dispersing, however, much faster.

EFFECTS OF SHORT-TERM EXPOSURE:
The substance is irritating to the eyes and the skin .

EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
The substance may have effects on the eyes , resulting in cataract.

PHYSICAL
PROPERTIES

Boiling point: 171°C
Melting point: < -60°C
Relative density (water = 1): 1.2
Solubility in water, g/100 ml at 20°C: >10
Vapour pressure, kPa at 20°C: 0.135
Flash point: 70°C c.c.
Auto-ignition temperature: 237°C
Explosive limits, vol% in air: 5.8-38.1
Octanol/water partition coefficient as log Pow: -1.2

ENVIRONMENTAL
DATA

The substance is harmful to aquatic organisms.

N O T E S

Do NOT use in the vicinity of a fire or a hot surface, or during welding.

ADDITIONAL INFORMATION



ICSC: 1599 DIMETHYL HYDROGEN PHOSPHITE
(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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