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Zinc Dialkyldithiophosphate (ZDDP)

  • Corrosion inhibitors
  • CAS 68457-79-4
  • IUPAC: zinc bis(O,O-dialkyl dithiophosphate)

CarCareTruth tracks Zinc Dialkyldithiophosphate (ZDDP) (CAS 68457-79-4) as a car-care ingredient.

Harmful if swallowed (H302). May cause an allergic skin reaction (H317). Toxic to aquatic life with long-lasting effects (H411). Signal word WARNING. Heavy metal content (zinc) and endocrine disruption in aquatic organisms at elevated concentrations.

ZDDP (zinc dialkyldithiophosphate) is the primary anti-wear additive in conventional and many synthetic motor oils. It forms a protective tribofilm on metal surfaces, preventing wear on camshafts and lifters — particularly important for flat-tappet engines.

ZDDP levels have been reduced in modern API SN/SP oils due to catalytic converter compatibility concerns (phosphorus poisons the catalyst). Older engines with flat-tappet cams often require supplemental ZDDP additives.

endocrine_disruptor: true — zinc ions have documented endocrine disruption effects in aquatic organisms. heavy_metal_containing: true — zinc.

Regulatory status

  • Not Prop 65 listed in the US
  • EU classified as environmentally hazardous (H411)

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
yes
Biodegradable
no
Bioaccumulative
no
Persistent
yes
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
2/5
Purpose: Primary anti-wear additive in motor oils; forms a protective tribofilm on metal surfaces

Common questions about Zinc Dialkyldithiophosphate (ZDDP)

What is Zinc Dialkyldithiophosphate (ZDDP) used for in car care?
Primary anti-wear additive in motor oils; forms a protective tribofilm on metal surfaces
Is Zinc Dialkyldithiophosphate (ZDDP) a VOC?
No. Zinc Dialkyldithiophosphate (ZDDP) is not classified as a volatile organic compound (VOC).
Is Zinc Dialkyldithiophosphate (ZDDP) on California's Proposition 65 list?
No. Zinc Dialkyldithiophosphate (ZDDP) is not on California's Proposition 65 list.

No products on file contain this (yet)

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.