Safety data sheet reference · CAS 144-62-7
Oxalic acid SDS
also: oxalic acid MSDS · safety data sheet · C2H2O4 · CAS 144-62-7 · EC 205-634-3
Official PDF from supplier
This page is a reference, not the legal document.
CAS number
144-62-7
EC number
205-634-3
CLP Annex VI index
607-006-00-8
Molecular formula
C2H2O4
Molar mass
90.03 g/mol
§ 02 · Hazards identification
Oxalic acid harmonised EU classification
CLP Annex VI · Index 607-006-00-8. A supplier SDS may add self-classified hazards — this is the legal minimum.
Precautionary statements
Codes ending in a colon introduce the action that follows — on a label they are printed as combined statements, such as P305+P351+P338.
§ 03 · Composition and identifiers
Oxalic acid molecular structure
Oxalic acid is a molecular compound. The skeletal formula below is drawn from its PubChem SMILES string, and every value in this section is computed from that structure.
2D skeletal formula · C2H2O4
Functional group
carboxylic acid
Hybridisation
C sp² ×2 · O sp² ×4
Electron count
34 valence e⁻ · 8 lone pairs
Identifiers from PubChem (NIH, public domain). Structure diagram drawn with RDKit from the SMILES string. Geometry and hybridisation are computed from the connection table, not measured.
§ 04 · First-aid measures
Oxalic acid first aid measures
Call your national emergency number first. These are published first-aid measures, not medical advice, and they do not replace emergency services, a poison control centre or the supplier's safety data sheet.
§4–§6 below reproduce the CAMEO Chemicals entry OXALIC ACID. CAMEO publishes response data per product entry, so the entry can describe a solution, a refrigerated liquid or a molten form rather than the pure substance in §9 — check it matches what you are handling.
EYES
First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.
SKIN
IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.
INHALATION
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.
INGESTION
DO NOT INDUCE VOMITING. Corrosive chemicals will destroy the membranes of the mouth, throat, and esophagus and, in addition, have a high risk of being aspirated into the victim's lungs during vomiting which increases the medical problems. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. IMMEDIATELY transport the victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. Transport the victim IMMEDIATELY to a hospital.
Source: NTP, 1992 — via CAMEO Chemicals (NOAA), public domain.
§ 05 · Fire-fighting measures
Oxalic acid fire fighting measures
ERG 2024 · GUIDE 154 Substances - Toxic and/or Corrosive (Non-Combustible)ERG guidance is written per response guide, not per substance — Guide 154 covers every material assigned to it, so a few sentences reference other UN numbers in the same group.
Fire and explosion hazard
Special Hazards of Combustion Products: Generates poisonous gases
Extinguishing media and tactics
Fires involving this compound may be controlled with a dry chemical, carbon dioxide or Halon extinguisher.
Source: NTP, 1992 — via CAMEO Chemicals (NOAA), public domain. Entry: OXALIC ACID.
§ 06 · Accidental release measures
Oxalic acid spill and leak response
Containment and clean-up
Neutralizing Agents for Acids and Caustics: Lime or soda ash
Initial isolation and evacuation
IMMEDIATE PRECAUTIONARY MEASUREIsolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.
SPILLIncrease the immediate precautionary measure distance, in the downwind direction, as necessary.
FIREIf tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
Source: USCG, 1999 — via CAMEO Chemicals (NOAA), public domain. Entry: OXALIC ACID.
§ 07 · Handling and storage
Oxalic acid computed storage compatibility
Derived from CLP Annex VI classification and CAMEO reactive-group data — not copied from a PDF.
⛔ Never store with
↔ Keep separate
Full interactive verdict — reactions, gas release on contact, ADR forms →
§ 08 · Exposure controls
Oxalic acid exposure limits (IDLH)
IDLH
Immediately Dangerous to Life or Health
500 mg/m3
NIOSH Pocket Guide — Oxalic acid →
IDLH from the NIOSH Pocket Guide to Chemical Hazards (CDC, U.S. public domain), via CAMEO Chemicals. Occupational exposure limits — OSHA PEL, NIOSH REL and EU IOELV — are not published on this page yet.
§ 09 · Physical and chemical properties
Oxalic acid physical properties
Source: CAMEO Chemicals (NOAA, public domain); per-value source references stored in the database.
§ 10 · Stability and reactivity
Reactive group (CAMEO/NOAA): Acids, Carboxylic. Our database documents 22 incompatible and 19 caution reaction-partner groups for oxalic acid — including which combinations release gas on contact. See the per-partner breakdown with gas release →
22
Incompatible
19
Caution
§ 13 · Disposal considerations
Dispose of waste and residues in accordance with local and national regulations — in the EU under the Waste Framework Directive 2008/98/EC. Never discharge to drains or municipal waste; hand contaminated packaging and unused product to an authorised waste-disposal company. The supplier's SDS section 13 lists the applicable waste codes for the specific product.
MSDS vs SDS
Oxalic acid MSDS vs SDS: is there a difference?
MSDS (Material Safety Data Sheet) is the older name for the same document. In the US, OSHA's Hazard Communication Standard (2012) adopted the GHS-standardised 16-section Safety Data Sheet; in the EU the format is set by REACH Annex II. So a "oxalic acid MSDS" and a "oxalic acid SDS" refer to the same document — today it is issued as an SDS. Full breakdown of the differences →
Other organic acids in our database
Substance profile
What oxalic acid is
Physical and chemical properties with the conditions each value was measured under, synonyms, formula and the harmonised CLP classification →
Compliance hub
From classification to SDS
The classification above corresponds to Section 2 of a Safety Data Sheet. Learn how a compliant 16-section SDS is structured and authored →
GHS label maker
Build the label for oxalic acid
Pictograms, signal word and H-statements combined into a compliant label layout →
§ 16 · Sources
- Classification: Regulation (EC) No 1272/2008 (CLP), Annex VI
- Transport: UN ADR 2025 (UNECE), Table A
- Reactivity: NOAA CAMEO Chemicals reactive-group matrix (public domain)
- Physical properties: CAMEO Chemicals (NOAA, public domain) — per-value source references stored in the database
- Emergency response (§4–§6): ERG 2024 (PHMSA) · NIOSH Pocket Guide (CDC) · CHRIS (USCG) · NTP · EPA — via CAMEO Chemicals (NOAA), all US federal public domain, reproduced verbatim
- Substance data: PubChem · ECHA
Reference aid only. This page summarises the harmonised EU classification and computed storage guidance — it is not a Safety Data Sheet and does not replace one. Always verify hazards, handling and storage against the supplier's SDS (sections 7 and 10) and local regulations before use. Page updated 2026-08-11.
Frequently asked questions about oxalic acid
Is an MSDS the same as an SDS?
In practice, yes. MSDS (Material Safety Data Sheet) is the older name for the same document. In the US, OSHA's Hazard Communication Standard (2012) adopted the GHS-standardised 16-section Safety Data Sheet; in the EU the SDS format is set by REACH Annex II. A document you find labelled "oxalic acid MSDS" is today issued as an SDS.
What GHS pictograms does oxalic acid require?
Under the harmonised EU classification (CLP Annex VI), oxalic acid carries GHS07 with the signal word "Warning". Hazard statements: H312, H302. A supplier's SDS may add self-classified hazards on top of this harmonised minimum.
What should oxalic acid never be stored with?
Based on its storage class (Organic acids), oxalic acid must not share storage with: Bases; Cyanides & sulfides; Organic peroxides & self-reactives; Oxidizing acids; Oxidizers; Water-reactives. Verify against the supplier's SDS sections 7 and 10 before finalising storage.
Where can I download an official oxalic acid SDS PDF?
From your own supplier — an SDS is issued per product and supplier, so the correct PDF for an inspection is the one matching the product you actually purchased. The supplier links on this page lead to the official SDS libraries of major distributors.
Call emergency services first
112 in the EU · 911 in the US. This screen is published response information, not medical advice, and it does not replace emergency services, a poison centre or the supplier's safety data sheet.
Text below is the CAMEO Chemicals entry OXALIC ACID — confirm it matches the form in front of you.
01 · First aid
What to do for the person
EYES
First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.
SKIN
IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.
INHALATION
IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.
INGESTION
DO NOT INDUCE VOMITING. Corrosive chemicals will destroy the membranes of the mouth, throat, and esophagus and, in addition, have a high risk of being aspirated into the victim's lungs during vomiting which increases the medical problems. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. IMMEDIATELY transport the victim to a hospital. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. Transport the victim IMMEDIATELY to a hospital.
02 · Fire
Extinguishing and tactics
Fire and explosion hazard
Special Hazards of Combustion Products: Generates poisonous gases
Extinguishing media and tactics
Fires involving this compound may be controlled with a dry chemical, carbon dioxide or Halon extinguisher.
03 · Spill
Containment, isolation, evacuation
Containment and clean-up
Neutralizing Agents for Acids and Caustics: Lime or soda ash
Initial isolation and evacuation
IMMEDIATE PRECAUTIONARY MEASUREIsolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.
SPILLIncrease the immediate precautionary measure distance, in the downwind direction, as necessary.
FIREIf tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions.
Sources: ERG 2024 (PHMSA) · NIOSH Pocket Guide (CDC) · CHRIS (USCG) · NTP · EPA — via CAMEO Chemicals (NOAA), public domain. Text reproduced verbatim.