NIOSH Publication No. 2005-151:

NIOSH Pocket Guide to Chemical Hazards

September 2005

Oxalic acid

CAS
144-62-7

HOOCCOOH • 2H2O

RTECS
RO2450000
Synonyms & Trade Names

Ethanedioic acid, Oxalic acid (aqueous), Oxalic acid dihydrate
DOT ID & Guide

Exposure
Limits

NIOSH REL: TWA 1 mg/m3 ST 2 mg/m3
OSHA PEL: TWA 1 mg/m3
IDLH
500 mg/m3 See: 144627
Conversion
Physical Description
Colorless, odorless powder or granular solid. [Note: The anhydrous form (COOH)2 is an odorless, white solid.]
MW: 126.1
BP: Sublimes
MLT: 215°F (Sublimes)
Sol: 14%
VP: <0.001 mmHg
IP: ?

Sp.Gr: 1.90
Fl.P: ?
UEL: ?
LEL: ?

Combustible Solid
Incompatibilities & Reactivities

Strong oxidizers, silver compounds, strong alkalis, chlorites [Note: Gives off water of crystallization at 215°F and begins to sublime.]
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
First Aid
(See procedures)
Eye: Irrigate immediately
Skin: Water flush promptly
Breathing: Respiratory support
Swallow: Medical attention immediately
Respirator Recommendations
NIOSH/OSHA
Up to 25 mg/m3:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode
(APF = 25) Any powered air-purifying respirator with a high-efficiency particulate filter.
Up to 50 mg/m3:
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters.
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece
Up to 500 mg/m3:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
Escape:
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters./Any appropriate escape-type, self-contained breathing apparatus
Important additional information about respirator selection
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
Irritation eyes, skin, mucous membrane; eye burns; localized pain, cyanosis; shock, collapse, convulsions; kidney damage
Target Organs
Eyes, skin, respiratory system, kidneys
See also: INTRODUCTION   See ICSC CARD: 0529   See MEDICAL TESTS: 0170