Borax (B4Na2O7.10H2O)

1Identification

Name

Borax (B4Na2O7.10H2O)

IUPAC name

disodium;3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane;decahydrate

CAS number

1303-96-4

Molecular formula

B4H20Na2O17

Molecular weight

381.4 g/mol

InChIKey

CDMADVZSLOHIFP-UHFFFAOYSA-N

SMILES

B1(OB2OB(OB(O1)O2)[O-])[O-].O.O.O.O.O.O.O.O.O.O.[Na+].[Na+]

PubChem CID

16211214

Synonyms

BORAX, Borax decahydrate, Sodium borate decahydrate, Borax (B4Na2O7.10H2O), Sodium pyroborate decahydrate, Antipyonin, Borascu, Boricin, Solubor, Tronabor, Jaikin, Neobor, Bura, Gerstley borate

Recommended uses

• CIR ingredient: Sodium Borate
  Cosmetic Ingredient Review (CIR)
• Used as a preservative, antiseptic and fungicide; also used to manufacture glazes, enamels, soldering fluxes and cleaning compounds and to fireproof textiles and wood; [ACGIH] Boric acid and borates as tablets or powder are used to kill larvae in barns and other insects in houses. Rarely, they are sprayed as herbicides. [EPA: Recognition of Pesticide Poisonings] Used in photo developing bath; [www.ci.tucson.az.us/arthazards/medium.html] Borax (borax decahydrate) is found naturally in some salt lakes and alkaline soils. Boric acid is formed by crystallizing a solution of hydrochloric acid or sulfuric acid and borax. [Hawley]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Soldering [Category: Heat or Machine] Using Disinfectants or Biocides [Category: Clean] Farming (Pesticides) [Category: Industry] Photographic Processing [Category: Other] Textiles (Printing, Dyeing, or Finishing) [Category: Industry]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Abrasives Plating agent Etching agent Chelating agent Flame retardant Soil amendments (fertilizers)
  EPA Chemical Data Reporting (CDR)
• Other Adhesion/cohesion promoter Soil amendments (fertilizers) Not Known or Reasonably Ascertainable Flame retardant
  EPA Chemical Data Reporting (CDR)

Use categories: EPA Safer Chemical Functional Use Classes -> Enzymes and Enzyme Stabilizers · Safer Chemical Classes -> Yellow triangle - The chemical has met Safer Choice Criteria for its functional ingredient-class, but has some hazard profile issues · Cosmetics -> Buffering

Description

• The Expert Panel concludes that Sodium Borate and Boric Acid, in concentrations less than or equal to 5 percent, are safe as cosmetic ingredients when used as currently recommended; however, cosmetic formulations containing free Sodium Borate or Boric Acid at this concentration should not be used on infant skin or injured skin. Note: In 2003, the CIR Expert Panel considered available new data on these ingredients and reaffirmed the above conclusion.
  Cosmetic Ingredient Review (CIR)
• Borax is a mineral with formula of Na2B4O5(OH)4·8H2O. The IMA symbol is Brx.
  RRUFF Project
• RN given refers to boric acid (H2B4O7), di-Na salt; see also borax (sodium borate decahydrate)
  Medical Subject Headings (MeSH)

2Hazard identification

Signal word

Danger

Pictograms

GHS08

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

5 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

Fire hazards

• Not combustible.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• The basis for the TLV for inorganic borate compounds is irritation of the nose and respiratory tract. Studies of workers exposed to sodium borate dusts found no evidence of pulmonary function or reproductive impairment. [ACGIH] Repeated skin exposure may cause dermatitis; Toxic by ingestion with effects on the liver, kidneys, and CNS; [ICSC]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• (General first aid procedures) Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Soap wash - If this chemical contacts the skin, wash the contaminated skin with soap and water. Breathing: Respiratory support Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Cough. Sore throat.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• Wear self contained breathing apparatus for fire fighting if necessary.
  Hazardous Substances Data Bank (HSDB)
• Use extinguishing measures that are appropriate to local circumstances and the surrounding environment.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Spill cleanup

• Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust.
  Hazardous Substances Data Bank (HSDB)
• Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.
  Hazardous Substances Data Bank (HSDB)
• Prevent further leakage or spillage if safe to do so. Do not let product enter drains.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Well closed. Dry.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Separated from acids.
  Hazardous Substances Data Bank (HSDB)
• Keep container tightly closed in a dry and well-ventilated place.
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• /Workers should wear/ protective gloves. Local exhaust or breathing protection /are needed/.
  Hazardous Substances Data Bank (HSDB)
• Wear goggles or eye protection in combination with breathing protection if powder.
  Hazardous Substances Data Bank (HSDB)
• Provide appropriate exhaust ventilation at places where dust is formed.
  Hazardous Substances Data Bank (HSDB)
• Eye/face protection: Safety glasses with side-shields conforming to EN166 Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• Important additional information about respirator selection
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Incompatible materials and hazardous reactions

• Zirconium, strong acids, metallic salts.
  Hazardous Substances Data Bank (HSDB)
• Incompatible with alkaloidal salts, mercuric chloride, zinc sulfate, and other metallic salts. ... With gums and mineral acids.
  Hazardous Substances Data Bank (HSDB)
• Zirconium, strong acids, metallic salts
  The National Institute for Occupational Safety and Health (NIOSH)

Chemical stability

• Stable. When heated above about 62 °C, borax loses water of crystallization, first forming the pentahydrate and then anhydrous sodium tetraborate.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Eyes, skin, respiratory system
  The National Institute for Occupational Safety and Health (NIOSH)

Short-term exposure effects

• The substance is irritating to the eyes, skin and respiratory tract. The substance may cause effects on the central nervous system and kidneys. This may result in impaired functions.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• Repeated or prolonged contact with skin may cause dermatitis. The substance may have effects on the testes. Animal tests show that this substance possibly causes toxicity to human reproduction or development.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.
  Hazardous Substances Data Bank (HSDB)
• SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal.
  Hazardous Substances Data Bank (HSDB)
• Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber.
  Hazardous Substances Data Bank (HSDB)

14Transport information

Not available in the public sources we compile. Check Section 14 of the supplier's SDS.

How DOT hazard classes work →

15Regulatory information

• An exemption from the requirement of a tolerance is established for residues of the pesticidal chemical boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride), sodium borate and sodium metaborate, in or on raw agricultural commodities when used as an active ingredient in insecticides, herbicides, or fungicides preharvest or postharvest in accordance with good agricultural practices.
  Hazardous Substances Data Bank (HSDB)
• The Agency has reassessed the current exemptions from the requirement for tolerances from boric acid/sodium borate salts (see Table 6 for tolerance exemptions). As a result of this assessment, the Agency determined that the active tolerances exemptions should be maintained and are considered reassessed as safe under section 408(q) of the FFDCA. It should be noted however that the higher application rates for the swimming pool uses resulted in residential post-application scenarios which exceed the Agency's LOC. The high rates for these pool and spa uses must be deleted from the end-use product labels.
  Hazardous Substances Data Bank (HSDB)
• Borax is an indirect food additive for use only as a component of adhesives.
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 16211214 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.