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NIOSH

FLUOROSILICIC ACID

ICSC: 1233

Hexafluorosilicic acid
Dihydrogen hexafluorosilicate
Fluosilicic acid
Hydrosilicofluoric acid
F6H2Si / H2SiF6
Molecular mass: 144.1
ICSC # 1233 		CAS # 16961-83-4
RTECS # VV8225000
UN # 1778
EC # 009-011-00-5
October 27, 2004 Validated

TYPES OF HAZARD/ EXPOSURE

ACUTE HAZARDS/ SYMPTOMS

PREVENTION

FIRST AID/
FIRE FIGHTING

FIRE Not combustible. Gives off irritating or toxic fumes (or gases) in a fire.

In case of fire in the surroundings: use appropriate extinguishing media.
EXPLOSION


EXPOSURE
AVOID ALL CONTACT!
IN ALL CASES CONSULT A DOCTOR!
•INHALATION Burning sensation. Cough. Laboured breathing. Shortness of breath. Symptoms may be delayed (see Notes).
Ventilation, local exhaust, or breathing protection.
Fresh air, rest. Half-upright position. Refer for medical attention.
•SKIN Redness. Pain. Skin burns.
Protective gloves. Protective clothing.
Remove contaminated clothes. Rinse skin with plenty of water or shower. Immediately refer for medical attention.
•EYES Redness. Pain. Severe deep burns.
Face shield 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 Burning sensation. Abdominal cramps. Vomiting. Shock or collapse.
Do not eat, drink, or smoke during work.
Rinse mouth. Do NOT induce vomiting. Give plenty of water to drink. Refer for medical attention.

SPILLAGE DISPOSAL

STORAGE

PACKAGING & LABELLING

Personal protection: complete protective clothing including self-contained breathing apparatus. Collect leaking and spilled liquid in sealable iron containers as far as possible. Absorb remaining liquid in sand or inert absorbent and remove to safe place Do NOT let this chemical enter the environment.
Separated from strong bases, food and feedstuffs . Well closed.
Unbreakable packaging; put breakable packaging into closed unbreakable container. Do not transport with food and feedstuffs.
Note: B
C symbol
R: 34
S: 1/2-26-27-45
UN Hazard Class: 8
UN Packing Group: II
ICSC: 1233 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.

FLUOROSILICIC ACID

ICSC: 1233

I

M

P

O

R

T

A

N

T


D

A

T

A

PHYSICAL STATE; APPEARANCE:
FUMING COLOURLESS LIQUID , WITH PUNGENT ODOUR.

PHYSICAL DANGERS:


CHEMICAL DANGERS:
The substance decomposes on heating producing toxic fumes including hydrogen fluoride . The solution in water is a strong acid, it reacts violently with bases and is corrosive. Reacts with water or steam to produce toxic and corrosive fumes . Attacks glass and stoneware. Attacks many metals forming flammable/explosive gas (hydrogen - see ICSC 0001). This substance (anhydrous form) dissociates almost instantly into silicon tetrafluoride and corrosive and toxic hydrogen fluoride.

OCCUPATIONAL EXPOSURE LIMITS:
TLV: (as F) 2.5 mg/m3 as TWA; A4 (not classifiable as a human carcinogen); BEI issued; (ACGIH 2004).
MAK not established.


ROUTES OF EXPOSURE:
The substance can be absorbed into the body by inhalation of its aerosol and by ingestion.

INHALATION RISK:
No indication can be given about the rate in which a harmful concentration in the air is reached on evaporation of this substance at 20°C.

EFFECTS OF SHORT-TERM EXPOSURE:
The substance is corrosive to the eyes, the skin and the respiratory tract. Corrosive on ingestion. Inhalation of the vapour of this substance may cause lung oedema (see Notes). The effects may be delayed. Medical observation is indicated. See Notes.

EFFECTS OF LONG-TERM OR REPEATED EXPOSURE:
The substance may have effects on the bones and teeth , resulting in fluorosis.

PHYSICAL
PROPERTIES

Decomposes below boiling point
Melting point: see Notes
Relative density (water = 1): see Notes
Solubility in water:
miscible
Vapour pressure, kPa at 20°C: see Notes

ENVIRONMENTAL
DATA

This substance may be hazardous in the environment; special attention should be given to aquatic organisms.

N O T E S

Marketed only as aqueous solution. Solidification point for 60-70% solution: solidifies at about 19°C, forming a crystalline dihydrate. Melting point for 35% solution: <-30°C. Relative density for a 61% solution is 1.46 and for 35% solution is 1.38. Vapour pressure for a 35% solution is about 3 kPa. The symptoms of lung oedema often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation are therefore essential. Temperature of decomposition unknown in literature. Immediate administration of an appropriate inhalation therapy by a doctor or a person authorized by him/her, should be considered. Card has been partly updated in April 2005. See sections Occupational Exposure Limits, EU classification, Emergency Response.
Transport Emergency Card: TEC (R)-80S1778 and 80GC1-II+III

ADDITIONAL INFORMATION



ICSC: 1233 FLUOROSILICIC ACID
(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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