Ingredient Dictionary

CALCIUM OXIDE

Calcium oxide is a member of the class of calcium oxides of calcium and oxygen in a 1:1 ratio.

Definition

Calcium oxide is a member of the class of calcium oxides of calcium and oxygen in a 1:1 ratio. It has a role as a fertilizer.

Source: PubChem

US FDA substance register · UNII C7X2M0VVNH · registered name LIME (CALCIUM OXIDE) · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Keeps pH steadyBUFFERING

Safety & regulatory references

Not classified under Korea’s toxic-substance GHS list · existing chemical substance

Source: Korea toxic substances GHS register (NIER)

Other restriction: ban substances that deplete the ozone layer

Source: EU CosIng ingredient list

More data — names, identifiers, properties, test records, literature

Official labels & definitions

JCIA labelling name 酸化Ｃａ: 本品は、カルシウムの酸化物であり、次の化学式で表される。

Source: JCIA labelling names (Japan)

Names & identifiers

CALCIUM OXIDEINCI칼슘옥사이드Korean label name (MFDS standard)酸化ＣａJapanese labelling name

CAS No.chemical registry number: 1305-78-8
EC No.EU chemical inventory number: 215-138-9
DTXSIDUS EPA chemical ID: DTXSID5029631
DTXCIDUS EPA compound ID: DTXCID101323191

IUPAC: Calcium oxide
Molecular formula: CaO
Molecular weight: 56.077 g/mol

Measured properties

Appearance: Calcium oxide appears as an odorless, white or gray-white solid in the form of hard lumps. A strong irritant to skin, eyes and mucous membranes. Used in insecticides and fertilizers. · Dry Powder, Wet Solid, Other Solid, Large Crystals, CBI, Liquid
Odour: Odorless · odourless
Boiling point: 5162 °F at 760 mmHg (NIOSH, 2024) · 2850 °C
Melting point: 4662 °F (NIOSH, 2024) · 2613 °C
Solubility: Reacts with water (NIOSH, 2024) · Slightly soluble in water. Insoluble in ethanol. Soluble in glycerol
Density: 3.3 at 68 °F (USCG, 1999) - Denser than water, will sink · 3.34 g/cu cm
Stability: Readily absorbs carbon dioxide and water from air, becoming airslaked.
Colour: white
pH: 12.8
Melting/freezing point: 2570 ℃
Initial boiling point and range: 2850 ℃
Relative density: 3.3-3.4
Molecular weight: 56.1

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: PubChem · KOSHA safety data sheets (Korea)

What products actually use it for

What the 111 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

Binder35
Processing aids not otherwise specified12
Degradant/impurity (EPA)8
pH regulating agent7
Filler6
Stabilizing agent4
Chemical reaction regulator4
Intermediate4

19 other uses

Catalyst3
Dehydrating agent (desiccant)3
Drier3
Corrosion inhibitor2
Sealant (barrier)2
Abrasive2
Flux agent2
Diluent2
Soil amendments2
Thickening agent1
Viscosity modifier1
Adhesion/cohesion promoter1
Adsorbent1
Absorbent1
Dye1
Flavouring and nutrient1
Anti-caking agent1
Reducing agent1
Dispersing agent1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

8 skin studies and 5 eye studies are on record.

Classed as highly irritating1Classed as moderate1Classed as low4

The studies disagree (the most common conclusion covers 17%), so they do not establish that this ingredient is irritating. These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 13 studies

Studies Indicate No Significant Irritation
skin irritation: in vivo · Screening · OECD Guideline 404 (Acute Dermal Irritation / Corrosion) , adopted 1992-07-17 according to
Skin corrosion/irritation - Category 1
Skin Irritation · Screening
Category 2
Skin Irritation · Screening
Classification not possible
Skin Sensitization · Screening
Studies Indicate No Significant Irritation
skin irritation: in vivo · Screening · OECD Guideline 404 (Acute Dermal Irritation / Corrosion) according to EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion) according to
Not likely to be sensitizing
skin sensitisation: in vivo (LLNA) · Screening · according to OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay) according to EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Category 8.2C (Category 1C)
Skin Irritation · Read Across
Skin irritation - category 2
Skin Irritation · Screening
Corrosive or Irritation Persists for > 21 days
eye irritation: in vivo · Screening · OECD Guideline 405 (Acute Eye Irritation / Corrosion) , adopted 1987-02-24 according to
Category 1
Eye Irritation · Screening
Category 8.3A (Category 1)
Eye Irritation · Read Across
Eye damage - category 1
Eye Irritation · Screening
Studies Indicate No Significant Irritation
eye irritation: in vivo · Screening · OECD Guideline 405 (Acute Eye Irritation / Corrosion) according to EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion) according to