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Tricresyl Phosphate

  • Esters
  • CAS 1330-78-5
  • IUPAC: Phosphoric acid, tris(methylphenyl) ester

CarCareTruth tracks Tricresyl Phosphate (CAS 1330-78-5) as a car-care ingredient.

Reproductive toxin Cat 2 (H361) from mixed-isomer tricresyl phosphate. The ortho-cresyl isomer (TOCP) is a known neurotoxin causing organophosphate-induced delayed neuropathy (OPIDN); commercial TCP contains <1% ortho-isomer but the hazard classification still applies. Skin sensitizer Cat 1A (H317) possible at concentrate contact.

Tricresyl phosphate (TCP) is an organophosphate ester used historically as an anti-wear additive in aviation turbine oils (Type II and Type IV), gear lubricants, and hydraulic fluids. It forms a protective phosphate-ester film on metal surfaces under high contact pressure (boundary lubrication conditions), reducing cam/lifter and gear wear. The commercial grade is a mixture of ortho, meta, and para isomers of cresyl phosphate; regulatory action has focused on minimizing the neurotoxic ortho-cresyl isomer, which causes organophosphate-induced delayed neuropathy (OPIDN) at high doses. Modern commercial TCP formulations typically contain <1% ortho-isomer. TCP is acutely aquatically toxic (H400/H410 at ingredient level) and bioaccumulative (Log Kow 5.93), making disposal via oil-change pathways an environmental concern.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
yes
Biodegradable
no
Bioaccumulative
yes
Persistent
yes
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
2/5
Purpose: Organophosphate anti-wear additive; used in aviation engine oils, gear oils, and oil additive concentrates

Common questions about Tricresyl Phosphate

What is Tricresyl Phosphate used for in car care?
Organophosphate anti-wear additive; used in aviation engine oils, gear oils, and oil additive concentrates
Is Tricresyl Phosphate a VOC?
No. Tricresyl Phosphate is not classified as a volatile organic compound (VOC).
Is Tricresyl Phosphate on California's Proposition 65 list?
No. Tricresyl Phosphate 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.