Organophosphate flame retardant / plasticizer

Tricresyl phosphate in the bedroom

Tricresyl phosphate (TCP, also known as TMPP or tritolyl phosphate) is a mixture of organophosphate esters used as a flame retardant, plasticizer, and lubricant additive. IARC classifies it as Group 3 (not classifiable as to carcinogenicity). The primary toxicological concern with TCP is neurotoxicity: the ortho-cresyl isomer (TOCP, tri-ortho-cresyl phosphate) causes organophosphate-induced delayed neuropathy (OPIDN), a progressive paralysis of the extremities. TCP is found in indoor dust and has been at the centre of the aircraft cabin air quality debate over so-called 'fume events' involving jet engine oil contamination.

Tricresyl phosphate — Embr Bedroom Chemistry Atlas

At a glance

Chemical familyOrganophosphate — mixed isomer aryl phosphate ester (flame retardant, plasticizer, lubricant)
CAS number1330-78-5
ClassificationIARC Group 3 (not classifiable as to carcinogenicity to humans, Monographs Vol. 48, 1990). Primary toxicological concern: organophosphate-induced delayed neuropathy (OPIDN) from the ortho-isomer
Where you encounter itJet engine lubricants and hydraulic fluids; PVC plasticizer; flame retardant in some plastics; indoor dust; industrial coatings
Sleep micro-environment relevanceFound in indoor dust as a trace contaminant from plasticised materials and industrial sources. The aircraft fume event controversy brings attention to TCP in enclosed spaces

Regulatory & certification status

European UnionREACH registered substance. Subject to ongoing assessment. Not currently restricted under Annex XVII for consumer products. CLP Acute Tox. 4, STOT RE 1 (nervous system). Regulatory
United StatesListed under TSCA inventory. EPA hazard data. OSHA occupational exposure limit: 0.1 mg/m3 (TWA, for TOCP). No consumer product restriction. Regulatory
CanadaAssessed under the Chemicals Management Plan as part of the organophosphate grouping. Regulatory
InternationalIARC Group 3 (not classifiable as to carcinogenicity, Monographs Vol. 48, 1990). WHO/FAO reviewed for food contamination. Under scrutiny for aircraft cabin air quality. Regulatory

What it is

Tricresyl phosphate is a mixture of isomeric triaryl phosphate esters derived from cresol (methylphenol). Commercial TCP is a mixture of ortho-, meta-, and para-cresyl isomers. The critical toxicological distinction is between isomers: tri-ortho-cresyl phosphate (TOCP) causes OPIDN, a condition where damaged nerve axons in the peripheral nervous system lead to progressive weakness and paralysis of the hands and feet, appearing 1-4 weeks after exposure. The most infamous TOCP poisoning was the 1930 'Ginger Jake' paralysis incident in the United States, which affected an estimated 30,000-50,000 people who drank adulterated Jamaica ginger extract. IARC classified TCP as Group 3 in 1990, finding inadequate evidence for carcinogenicity.

Where it shows up in bedding

TCP is not a standard ingredient in bedding products. Its presence in the bedroom is as a trace contaminant in house dust, originating from plasticised PVC products, electronic equipment, and industrial sources. TCP is also present in indoor air near airports or in buildings with jet-engine-related contamination. For most bedrooms, TCP is a minor component of the organophosphate burden in dust, present at lower concentrations than the more common OPFRs like TCPP and TPHP.

The Embr Exposure Ledger: Tricresyl phosphate (TCP)

One chemical, several public questions, answered from independent datasets and joined here — the environment it shows up in, the body burden it carries, how it is regulated, and what actually reduces it.

This compound appears in 3 of the Embr Exposure Ledger’s 10 exposure datasets.
At what level would it matter?
EPA’s table carries this compound but publishes no inhalation reference value for it. What is above says it is present somewhere, not that any particular amount is harmful. Presence is not dose, and for this compound the inhalation side is not established in the sources this ledger draws on.Source: US EPA, Regional Screening Levels (RSL) Summary Table — consolidated toxicity values from IRIS, PPRTV, ATSDR, Cal EPA and OPP

Detection and body-burden figures are occurrence data, not a personal measurement or a health diagnosis. Part of the Embr Exposure Ledger — an open, cross-dataset chemical join (download the data), reusable with attribution.

Citations

  1. IARC (1990). Tri(2-tolyl) phosphate. IARC Monographs Vol. 48. Source Regulatory
  2. ATSDR (2012). Toxicological Profile for Phosphate Ester Flame Retardants. Source Regulatory
  3. ECHA. Tricresyl phosphate — Substance Information. Source Regulatory

Frequently asked questions

  • Does TCP in house dust cause nerve damage?

    At the trace concentrations found in household dust, TCP is extremely unlikely to cause OPIDN. The delayed neuropathy caused by the ortho-isomer (TOCP) requires substantial acute or repeated exposure far exceeding what residential dust levels represent. The historical mass-poisoning events involved ingestion of heavily contaminated food or drink. However, TCP in dust contributes to cumulative organophosphate exposure.

  • What are aircraft fume events?

    Fume events are incidents where jet engine oil (which contains TCP) leaks into the aircraft cabin air supply through bleed-air systems. Passengers and crew may be exposed to TCP vapours. The health effects of these exposures are debated — some affected crew members report neurological symptoms, while aviation authorities and engine manufacturers dispute the risk at measured exposure levels. The controversy centres on the ortho-isomer content of modern jet oils.

Related compounds


Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.

Last reviewed 2026-07-08. If you find a factual error, contact us.