Sulfuric Acid
- Acids
- CAS 7664-93-9
- IUPAC: Sulfuric acid
Sulfuric Acid (CAS 7664-93-9) appears in 1 of the 2,122 car-care products CarCareTruth tracks (as of August 2026). It is listed on California's Proposition 65.
Sulfuric acid is California Proposition 65-listed for carcinogenicity and developmental/reproductive toxicity (strong inorganic acid mists). Pure concentrated sulfuric acid is H314 (skin corrosion, serious eye damage). In car-care surfactant products it is not an intentional ingredient - it is a manufacturing byproduct of sulfonating agents used to make anionic surfactants (e.g., alkylbenzene sulfonic acid, sodium C-alkyl sulfates). Several Chemical Guys SDSs name it directly in Section 15 as the trigger for the mandatory California warning without disclosing a concentration; per CCT's fail-safe scoring convention, an undisclosed concentration is treated as the highest exposure tier rather than assumed trace.
Sulfuric acid (CAS 7664-93-9) is a California Proposition 65-listed substance (carcinogenicity and developmental/reproductive toxicity) that shows up as a named trigger in the Section 15 regulatory tables of several Chemical Guys surfactant-based wash products. It is not disclosed as a Section 3 formulation ingredient at any concentration - manufacturers encounter it as a residual byproduct of the sulfonation chemistry used to produce anionic surfactants (alkylbenzene sulfonic acid, sodium alkyl ether sulfates, and similar), not as something deliberately added.
Because no concentration is disclosed anywhere in the SDS for these products, CarCareTruth's scoring treats the exposure as the least-favorable (highest) tier rather than assuming a low trace level it cannot verify. This is a source-transparency gap in the manufacturer's own SDS, not a claim that the product's actual sulfuric acid content is unusually high. Pure, concentrated sulfuric acid is a strong corrosive (H314); at the trace/residual levels implied by a surfactant-synthesis byproduct, the finished consumer product itself is not classified as corrosive under GHS.
Regulatory status
- California Prop 65 listed for cancer: "Strong inorganic acid mists containing sulfuric acid," listed 2003-03-14 (mechanism: Authoritative Body). The OEHHA listing carries no CAS number of its own, a category-style listing scoped to the acid-mist exposure route, the same pattern as this catalog's crystalline-silica and titanium-dioxide listings, and is matched here by name rather than by CAS 7664-93-9 directly.
Sources
- OEHHA Proposition 65 list cross-check:
data/prop65/oehha-list.json(986 entries, published 2025-12-05), name match "Strong inorganic acid mists containing sulfuric acid," cancer, dateListed 2003-03-14, no CAS assigned. Found and documented while validating thecontent:audit-prop65-citationschecker built in this same pass; this file previously assertedprop65_listed: truewithout a Sources or Regulatory status section, which the checker correctly flagged as unverifiable on its face even though the underlying flag is accurate.
Related: Is Battery Acid Toxic? Read the full SDS breakdown of the lead-acid car battery whose electrolyte is this same acid in dilute form.
Health & environment profile
- VOC
- no
- Prop 65 listed
- yes
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- yes
- Biodegradable
- no
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 3/5
Common questions about Sulfuric Acid
- What is Sulfuric Acid used for in car care?
- Process residual / surfactant-synthesis byproduct - not an intentional cleaning ingredient. Named directly by several Chemical Guys product SDSs (Section 15) as the substance triggering the mandatory California Prop 65 warning, without a disclosed concentration or a Section 3 role.
- Is Sulfuric Acid a VOC?
- No. Sulfuric Acid is not classified as a volatile organic compound (VOC).
- Is Sulfuric Acid on California's Proposition 65 list?
- Yes. Sulfuric Acid appears 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.