Calcium Hydroxide (Calcium Dihydroxide)
- Bases
- CAS 1305-62-0
- IUPAC: Calcium dihydroxide
Calcium Hydroxide (Calcium Dihydroxide) (CAS 1305-62-0) appears in 1 of the 1,812 car-care products CarCareTruth tracks (as of June 2026).
Classified as corrosive/irritant at high concentrations. Skin irritation (H315) and eye irritation/damage potential at concentrations present in anti-seize compounds. In the context of a paste at 10–30% concentration with the paste chemistry, contributes to the skin irritation classification of the mixture. ACGIH TLV-TWA: 5 mg/m³. Oral LD50 (Rat): 7,340 mg/kg.
Calcium hydroxide (CAS 1305-62-0), also called slaked lime or calcium dihydroxide, is an inorganic base produced by combining calcium oxide (quicklime) with water. In anti-seize pastes, it functions as a filler and structural component of the paste matrix, contributing to the consistency and body of the product alongside the petroleum-grease carrier.
At high concentrations calcium hydroxide is a primary irritant to skin and eyes (the strongly alkaline pH causes saponification of lipids in skin at sustained contact), but in the 10–30% range typical in anti-seize compound, it contributes to the skin irritation classification of the mixture without the corrosive severity seen at higher concentrations or in concentrated lime products. The oral LD50 in rats (7,340 mg/kg) reflects low acute oral toxicity.
Calcium hydroxide is not classified under Prop 65 and does not present aquatic toxicity or bioaccumulation concerns at environmental concentrations.
Health & environment profile
- VOC
- no
- Prop 65 listed
- no
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- no
- Biodegradable
- no
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 3/5
Common questions about Calcium Hydroxide (Calcium Dihydroxide)
- What is Calcium Hydroxide (Calcium Dihydroxide) used for in car care?
- Filler and pH modifier in anti-seize pastes; provides bulk consistency and acts as a corrosion inhibitor for certain metal surfaces
- Is Calcium Hydroxide (Calcium Dihydroxide) a VOC?
- No. Calcium Hydroxide (Calcium Dihydroxide) is not classified as a volatile organic compound (VOC).
- Is Calcium Hydroxide (Calcium Dihydroxide) on California's Proposition 65 list?
- No. Calcium Hydroxide (Calcium Dihydroxide) is not on California's Proposition 65 list.
1 product contain this
Prop 65
Related
Health and environment notes translate the manufacturer Safety Data Sheet, the GHS classification, and authoritative regulatory listings (California Prop 65, EPA). Not medical advice. They describe the ingredient itself; whether a hazard applies to a finished product depends on its concentration and how it's used.