Annex III
Entry 15c
17/10/2010
CALCIUM HYDROXIDE
Calcium hydroxide
CALCIUM HYDROXIDE is listed in Annex III and may only be used under the conditions shown in this record. Maximum concentration in this record: (a) 7% (as calcium hydroxide).
Restricted substance— Annex III, EU Regulation 1223/2009
Max conc.: (a) 7% (as calcium hydroxide)
Entry: 15c
Chemical identity and properties
CAS 1305-62-0PubChem CID 6093208
Calcium Hydroxide
Calcium dihydroxide is a calcium hydroxide. It has a role as an astringent. — ChEBI
- IUPAC name
- calcium dihydroxide
- Molecular formula
- CaH2O2
- Molecular weight
- 74.09 g/mol
- Exact mass
- 73.9680702 Da
- Topological polar surface area
- 2.0 Ų
- Hydrogen-bond donors
- 2
- Hydrogen-bond acceptors
- 2
- Covalent units
- 3
- Defined stereocentres
- 0
Also known as
Slaked limeHydrated limeLime hydrateCalcium hydrateLime waterCalcium hydroxide (Ca(OH)2)HydralimeSlaked-lime
16 more reported names
Lime milkCalcarea causticaINS NO.526PF5DZW74VNE-526CHEBI:31341Hydroxide, Calcium215-137-3O2 PatchRefChem:54625KO2, Ca(OH)2CHEBI:35150620-122-3Bell mineBiocalcCalbit
External database identifiers
- ChEBI:CHEBI:31341
- ChEMBL:CHEMBL2106388
- PubMed:30615914
- PubMed:22083529
Evidence from additional scientific databases
NIH PubChem PUG-View
Exact identifier match6093208
Attributed physical-property, hazard, environmental and use annotations.
- Autoignition Temperature: Not flammable (USCG, 1999) Source: CAMEO Chemicals
- Boiling Point: Decomposes (NIOSH, 2024) Source: CAMEO Chemicals
- Boiling Point: Decomposes Source: Hazardous Substances Data Bank (HSDB)
- Boiling Point: decomposes Source: Occupational Safety and Health Administration (OSHA)
- Boiling Point: Decomposes Source: The National Institute for Occupational Safety and Health (NIOSH)
- Color/Form: Crystals or soft granules or powder Source: Hazardous Substances Data Bank (HSDB)
- Color/Form: Soft, hexagonal crystals Source: Hazardous Substances Data Bank (HSDB)
- Color/Form: Rhombic, trigonal, colorless crystals Source: Hazardous Substances Data Bank (HSDB)
- Color/Form: Soft, white crystalline powder Source: Hazardous Substances Data Bank (HSDB)
- Color/Form: White powder [Note: Readily absorbs CO2 from the air to form calcium carbonate] Source: Hazardous Substances Data Bank (HSDB)
- Density: 2.24 at 68 °F (USCG, 1999) - Denser than water; will sink Source: CAMEO Chemicals
- Density: Approximately 2.2 g/cu cm Source: Hazardous Substances Data Bank (HSDB)
- Density: Bulk density: 450 to 640 kg/cu m. In the as-poured state, it can be as low as 350 kg/cu m, owing to air entrapment Source: Hazardous Substances Data Bank (HSDB)
- Density: Relative density (water = 1): 2.2 Source: ILO-WHO International Chemical Safety Cards (ICSCs)
- Density: 2.24 Source: Occupational Safety and Health Administration (OSHA)
- Density: 2.343 @25 °C Source: PAC Chemical Database, U.S. Department of Energy
- Density: 2.24 Source: The National Institute for Occupational Safety and Health (NIOSH)
- Flash Point: /Calcium Hydroxide is/ non flammable Source: Hazardous Substances Data Bank (HSDB)
- Melting Point: 1076 °F (Decomposes) (Loses H2O) (NIOSH, 2024) Source: CAMEO Chemicals
- Melting Point: 1076 °F (decomposes) (loses water) Source: Hazardous Substances Data Bank (HSDB)
- Melting Point: 1076 °F (decomposes) (loses H₂O) Source: Occupational Safety and Health Administration (OSHA)
- Melting Point: 1076 °F (Decomposes) (Loses H2O) Source: The National Institute for Occupational Safety and Health (NIOSH)
- Odor: Odorless Source: Hazardous Substances Data Bank (HSDB)
- Physical Description: Calcium hydroxide is an odorless white granules. Sinks in water. (USCG, 1999) Source: CAMEO Chemicals
- Physical Description: Dry Powder; Other Solid; Liquid; Other Solid; Liquid; Liquid; Wet Solid; CBI; Dry Powder; Wet Solid; Large Crystals; Wet Solid; Other Solid; Dry Powder; Gas Vapor Source: EPA Chemical Data Reporting (CDR)
- Physical Description: White powder Source: EU Food Improvement Agents
- Physical Description: White, odorless powder; Note: Readily absorbs CO2 from the air to form calcium carbonate; [NIOSH] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Physical Description: COLOURLESS CRYSTALS OR WHITE POWDER. Source: ILO-WHO International Chemical Safety Cards (ICSCs)
- Physical Description: White, odorless powder. Source: Occupational Safety and Health Administration (OSHA)
- Physical Description: White, odorless powder. [Note: Readily absorbs CO2 from the air to form calcium carbonate.] Source: The National Institute for Occupational Safety and Health (NIOSH)
- Refractive Index: Index of refraction: 1.574 (alpha), 1.545 (beta) Source: Hazardous Substances Data Bank (HSDB)
- Solubility: 0.2 % at 32 °F (NIOSH, 2024) Source: CAMEO Chemicals
- Solubility: Slightly soluble in water. Insoluble in ethanol. Soluble in glycerol Source: EU Food Improvement Agents
- Solubility: Solubility in water is decreased by the presence of fixed alkali hydroxides. Source: Hazardous Substances Data Bank (HSDB)
- Solubility: In water, 1730 mg/L at 20 °C Source: Hazardous Substances Data Bank (HSDB)
- Solubility: In water, 0.160 g/100 g water at 20 °C Source: Hazardous Substances Data Bank (HSDB)
- Solubility: Very slightly soluble in boiling water. Insoluble in alcohol. Source: Hazardous Substances Data Bank (HSDB)
- Solubility: Soluble in acid Source: Hazardous Substances Data Bank (HSDB)
- Solubility: Soluble in glycerol, sugar or ammonium chloride solution; soluble in acids with evolution of much heat Source: Hazardous Substances Data Bank (HSDB)
- Solubility: Solubility in water: none Source: ILO-WHO International Chemical Safety Cards (ICSCs)
- Solubility: (32 °F): 0.2% Source: The National Institute for Occupational Safety and Health (NIOSH)
- Vapor Pressure: 0 mmHg (approx) (NIOSH, 2024) Source: CAMEO Chemicals
- Vapor Pressure: 0 mmHg (approx) Source: Occupational Safety and Health Administration (OSHA)
- Vapor Pressure: 0 mmHg (approx) Source: The National Institute for Occupational Safety and Health (NIOSH)
- pH: pH = 12.4 (aqueous solution saturated at 25 °C) Source: Hazardous Substances Data Bank (HSDB)
- Exposure Routes: The substance can be absorbed into the body by inhalation of its aerosol and by ingestion. Source: ILO-WHO International Chemical Safety Cards (ICSCs)
- Exposure Routes: inhalation, ingestion, skin and/or eye contact Source: The National Institute for Occupational Safety and Health (NIOSH)
- First Aid: Excerpt from NIOSH Pocket Guide for Calcium hydroxide:; 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 FLUSH IMMEDIATELY - If this chemical contacts the skin, immediately flush the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. If irritation persists after washing, get medical attention.; Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.; Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024) Source: CAMEO Chemicals
- First Aid: (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 flush immediately - If this chemical contacts the skin, immediately flush the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. If irritation persists after washing, get medical attention.; Breathing: Respiratory support; Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately. Source: The National Institute for Occupational Safety and Health (NIOSH)
- Note: This chemical does not meet GHS hazard criteria for 0.4% (28 of 6644) of reports. Source: European Chemicals Agency (ECHA)
- Signal: Danger Source: European Chemicals Agency (ECHA)
- GHS Hazard Statements: H314 (22.4%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]; H315 (45.3%): Causes skin irritation [Warning Skin corrosion/irritation]; H318 (76.9%): Causes serious eye damage [Danger Serious eye damage/eye irritation]; H335 (38.9%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation] Source: European Chemicals Agency (ECHA)
- Precautionary Statement Codes: P260, P261, P264, P264+P265, P271, P280, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P319, P321, P332+P317, P362+P364, P363, P403+P233, P405, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
- ECHA C&L Notifications Summary: Aggregated GHS information provided per 6644 reports by companies from 59 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Reported as not meeting GHS hazard criteria per 28 of 6644 reports by companies.; There are 56 notifications provided by 6616 of 6644 reports by companies with hazard statement code(s).; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
- GHS Hazard Statements: Not Classified; Reported as not meeting GHS hazard criteria by 1 of 1 companies. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
- Signal: Danger Source: NITE-CMC
- GHS Hazard Statements: H315: Causes skin irritation [Warning Skin corrosion/irritation]; H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]; H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure] Source: NITE-CMC
- Precautionary Statement Codes: P260, P264, P264+P265, P270, P280, P302+P352, P305+P354+P338, P308+P316, P317, P321, P332+P317, P362+P364, P405, and P501 (click each P-code to see the statement) Source: NITE-CMC
- GHS Hazard Statements: H315: Causes skin irritation [Warning Skin corrosion/irritation]; H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]; H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]; H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure] Source: NITE-CMC
- Precautionary Statement Codes: P260, P264, P264+P265, P270, P280, P302+P352, P305+P354+P338, P308+P316, P317, P319, P321, P332+P317, P362+P364, P405, and P501 (click each P-code to see the statement) Source: NITE-CMC
- Signal: Danger Source: Hazardous Chemical Information System (HCIS), Safe Work Australia
- Target Organs: Eyes, skin, respiratory system Source: The National Institute for Occupational Safety and Health (NIOSH)
- Cosmetic Ingredient Review Conclusion: The CIR Expert Panel concluded that ... Calcium Hydroxide is safe in hair straighteners and depilatories under conditions of recommended use; users should minimize skin contact. These ingredients are safe for all other present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Source: Cosmetic Ingredient Review (CIR)
- Cosmetic Ingredient Review Finding(s): Safe for use in cosmetics, with qualifications Source: Cosmetic Ingredient Review (CIR)
- Environmental Bioconcentration: This compound shows no bioaccumulation or food chain concentration toxicity potential. Source: Hazardous Substances Data Bank (HSDB)
- Environmental Fate: Aquatic Fate: Aquatic toxicity is the function of an alkalinity effect. Addition of lime to soft water lakes has increased biological activity, possibly by providing a carbon dioxide reservoir. Source: Hazardous Substances Data Bank (HSDB)
- Environmental Fate: Calcium hydroxide does not degrade by photooxidation; it is neutralized by absorption of atmospheric carbon dioxide. Source: Hazardous Substances Data Bank (HSDB)
- Consumer Uses: Chemical reaction regulator; pH regulating agent; Other; Lubricating agent; Adhesion/cohesion promoter; Flocculating agent; Heat stabilizer; Intermediate; Reducing agent; Soil amendments (fertilizers); Filler; Not Known or Reasonably Ascertainable; Absorbent Source: EPA Chemical Data Reporting (CDR)
- Industry Uses: Other; Binder; Lubricating agent; Processing aids not otherwise specified; Chemical reaction regulator; Fuel agents; pH regulating agent; Fuel; Antioxidant; Flux agent; Absorbent; Dehydrating agent (desiccant); Sealant (barrier); Reducing agent; Stabilizing agent; Flow promoter; Catalyst; Filler; Diluent; Not Known or Reasonably Ascertainable; Corrosion inhibitor; Soil amendments (fertilizers); Solids separation (precipitating) agent, not otherwise specified; Hardener; Flocculating agent; Adhesion/cohesion promoter; Processing aids, specific to petroleum production; Intermediate; Softener and conditioner; Oxidizing agent; Adsorbent Source: EPA Chemical Data Reporting (CDR)
- Cosmetic Ingredient Review Link: CIR ingredient: Calcium Hydroxide Source: Cosmetic Ingredient Review (CIR)
- Sources/Uses: Used in mortar, plaster, cement, lubricants, drilling fluids, paper pulp, and water treatment; also used to dehair hides; [ACGIH] Used in pesticides, fireproofing coatings, water-based paints, SBR rubber vulcanization, binding and paving materials, soil treatments, brewing manufacture, dental cements, petrochemicals, as chemical intermediate, buffering agent for metals, pearls, and celluloid, disinfectant, food additive, for ammonia recovery in gas manufacture, purification of sugar juices, to preserve eggs and apples during storage, in cattle feeds, and veterinary medicine; [HSDB] Used as both an inert and active ingredient (microbiocide/microbiostat) in pesticide products; [EPA REDs] Used as a nutritional supplement, pH control agent, firming agent, and processing aid for foods; [FDA] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Industrial Processes with risk of exposure: Petroleum Production and Refining [Category: Industry]; Pulp and Paper Processing [Category: Industry]; Painting (Pigments, Binders, and Biocides) [Category: Paint]; Using Disinfectants or Biocides [Category: Clean]; Farming (Pesticides) [Category: Industry]; Sewer and Wastewater Treatment [Category: Industry]; Leather Tanning and Processing [Category: Industry]; Cement Producing [Category: Industry]; Farming (Feed Additives) [Category: Industry] Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
- Uses: For calcium hydroxide (USEPA/OPP Pesticide Code: 075601) ACTIVE products with label matches. /SRP: Registered for use in the USA but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./ Source: Hazardous Substances Data Bank (HSDB)
- Uses: In mortar, plaster, cement and other binding and paving materials; in lubricants, drilling fluid, pesticides, fireproofing coatings, water paint; as egg preservative; manufacture of paper pulp; in SBR rubber vulcanization; in water treatment; as absorbant for carbon dioxide; dehairing hides. Source: Hazardous Substances Data Bank (HSDB)
- Uses: Chem int in chlorohydrin process for propylene oxide /former use/; chem int for calcium hypochlorite, bleaching powder, and the fungicide, lime-sulfur spray; flux in iron and steel mfr; soil treatment for acidic soils; water softening agent; stabilization of soils for road base; component of sand-lime bricks and blocks; component of masonary mortar; water correcting agent in brewing mfr; component of dental cement; buffering agent for metals, pearls and celluloid. Source: Hazardous Substances Data Bank (HSDB)
- Uses: Calcium salts, causticizing soda, depilatory, whitewash, soil conditioner, ammonia recovery in gas manufacturing, disinfectant, water softening, purification of sugar juices, petrochemicals, food additive as buffer and neutralizing agent, shell-forming agent (poultry) Source: Hazardous Substances Data Bank (HSDB)
- Uses: For more Uses (Complete) data for CALCIUM HYDROXIDE (13 total), please visit the HSDB record page. Source: Hazardous Substances Data Bank (HSDB)
Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record
Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.
Additional source coverage and match status
| Source | Result | Checked |
|---|---|---|
| NIH PubChem PUG-View | Exact match | 2026-08-31 |
A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.
Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.
Record details
Maximum concentration
(a) 7% (as calcium hydroxide)
Product type
Other restrictions
(b) pH < 12.7
(c) pH < 11
Warnings
(a) Contains alkali
Avoid contact with eyes
Keep out of reach of children
Can cause blindness
(b) Contains alkali
Keep out of reach of children
Avoid contact with eyes
INCI glossary name
CALCIUM HYDROXIDE
Chemical name
Calcium hydroxide
Regulatory information
SCCS opinions
Identified ingredients
Key data
Inventory links for CALCIUM HYDROXIDE
Related records for CALCIUM HYDROXIDE
Direct matches are limited for this record, so nearby entries from Annex III are shown as well.
Annex III
15a
Nearby record in the same annex
POTASSIUM HYDROXIDE / SODIUM HYDROXIDE
CAS: 1310-58-3 / 1310-73-2
EC: 215-181-3 / 215-185-5
What Annex III means for CALCIUM HYDROXIDE
CALCIUM HYDROXIDE is a restricted substance under Annex III of EU Cosmetics Regulation 1223/2009. Its use in cosmetics is only permitted under the specific conditions set out in the entry above, including applicable concentration limits, product type restrictions and required warning statements.
When including this substance in a formulation, all conditions — maximum concentration, product scope and warning labels — must be met simultaneously. Compliance with one condition does not override the others.
This record is linked to 1 CosIng inventory ingredient for name and identifier cross-reference. The page also surfaces 11 related annex records with overlapping identifiers, annex logic or naming patterns.
Compliance checklist
- Ensure formulation concentration does not exceed: (a) 7% (as calcium hydroxide)
- Confirm product type compatibility: (a) Hair straighteners containing two components: calcium hydroxide and a guanidine salt (b) pH ajuster for depilatories (c) Other uses (e.g. pH adjuster, processing aid)
- Include required warning statement on product label.
- Document conditions of use in the Product Information File (PIF).
Frequently asked questions
CALCIUM HYDROXIDE is listed in Annex III of EU Regulation 1223/2009 as a restricted substance. It may only be used under the conditions specified in the entry, including any maximum concentration, product type limitation and required warning statements shown above.
CAS 1305-62-0 is the unique numerical identifier assigned to CALCIUM HYDROXIDE by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.
The maximum concentration of (a) 7% (as calcium hydroxide) applies to the concentration of the substance in the ready-to-use cosmetic product. When the substance is supplied as part of a blend or mixture, the calculation must account for the contribution of all sources in the formulation. The combined concentration must not exceed the stated limit.
Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
Source note for Annex III record CALCIUM HYDROXIDE
This page summarizes one Annex III record for CALCIUM HYDROXIDE from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.
Use this record page to review Annex III conditions for CALCIUM HYDROXIDE, but confirm any final regulatory decision against the current official annex wording and source files.
Tools & next steps
Check your formula
Paste a full INCI list to detect CALCIUM HYDROXIDE and other flagged EU annex records in one pass.
INCI CheckerCompare entries
Compare CALCIUM HYDROXIDE side by side with another annex record to review differences in restrictions, concentrations and annex placement.
CompareBrowse the annex
See all records in Annex III and compare regulatory conditions across substances in this annex.
Open Annex III