NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Sodium metabisulfite

CAS
7681-57-4

Na2S2O5

RTECS
UX8225000
Synonyms & Trade Names

Disodium pyrosulfite, Sodium metabisulphite, Sodium pyrosulfite
DOT ID & Guide

Exposure
Limits

NIOSH REL: TWA 5 mg/m3
OSHA PEL: none
IDLH
N.D. See: IDLH INDEX
Conversion
Physical Description
White to yellowish crystals or powder with an odor of sulfur dioxide.
MW: 190.1
BP: Decomposes
MLT: >302°F (Decomposes)
Sol: 54%
VP: ?
IP: NA

Sp.Gr: 1.4
Fl.P: NA
UEL: NA
LEL: NA

Noncombustible Solid
Incompatibilities & Reactivities

Heat (decomposes) [Note: Slowly oxidized to the sulfate on exposure to air & moisture.]
Measurement Methods
NIOSH 0500
See: NMAM or OSHA Methods
Personal Protection & Sanitation
(See protection)
Skin: No recommendation
Eyes: No recommendation
Wash skin: No recommendation
Remove: No recommendation
Change: No recommendation

First Aid
(See procedures)
Eye: Irrigate immediately

Breathing: Fresh air
Swallow: Medical attention immediately
Respirator Recommendations
Not available.
Important additional information about respirator selection
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
Irritation eyes, skin, mucous membrane
Target Organs
Eyes, skin, respiratory system
See also: INTRODUCTION