Tricresyl phosphate (TCP, also called tritolyl phosphate; CAS 1330-78-5) is a triaryl phosphate ester used as a flame-retardant plasticizer in flexible PVC and cellulosic plastics, where one additive both softens the compound and adds phosphorus for fire performance. Because commercial TCP is a mixture of cresyl isomers, and its ortho-cresyl isomers are linked to delayed neurotoxicity, the first question a buyer asks is which isomers a grade contains.
Tricresyl phosphate is not on the REACH Candidate List (253 entries, last updated 4 February 2026), Annex XIV or Annex XVII, is not a persistent organic pollutant and is not on the Union list of Regulation (EU) No 10/2011 (consolidated text of 14 July 2026), while its xylyl analogue trixylyl phosphate has been a Substance of Very High Concern since 16 December 2013. Among plastic additives, TCP is one of the phosphate esters in our database of plastic additives that sit in two families at once, plasticizers and flame retardants.
This page sets out the TCP and TCPP name confusion, the isomer mixture behind one CAS number, how TCP plasticizes and flame-retards, its use in flexible PVC and cellulosics, the fire tests that judge it, the dated EU matrix with the trixylyl phosphate contrast and the open US record, the ortho-isomer hazard, 5 alternatives and the 5 documents to request from a supplier.
Table T1. Tricresyl phosphate identity record.
| Field | Value |
|---|---|
| Name | tricresyl phosphate |
| Abbreviation | TCP |
| Synonyms | tritolyl phosphate; tris(methylphenyl) phosphate |
| CAS number | 1330-78-5 (isomer mixture) |
| EC number | 215-548-8 |
| Molecular formula | C21H21O4P |
| Molecular weight | 368.4 g/mol (calculated from the formula) |
| Chemical class | triaryl phosphate ester (phosphate ester plasticizer; organophosphate flame retardant) |
| Function in plastics | flame-retardant plasticizer for PVC and cellulosics |
| Ortho isomer | TOCP (tri-ortho-cresyl phosphate); its CAS number is not yet recorded in our source library |
| Trade names | not recorded in our source library |
| EU REACH | not an SVHC; not on Annex XIV; not restricted under Annex XVII |
| EU 10/2011 | not on the Union list (Annex I) |
| EU POPs | not listed |
| Not to be confused with | TCPP, tris(2-chloro-1-methylethyl) phosphate, CAS 13674-84-5; trixylyl phosphate (TXP), CAS 25155-23-1 |
Footnote: identity data from PubChem and ECHA CHEM; knowledge base check 22 September 2026. Regulatory entries are dated in Table T5.
Request a quote for TCP
Send one short specification and compare the replies from producers and distributors.
What Is Tricresyl Phosphate (TCP)?#
Tricresyl phosphate is the triester of phosphoric acid with three cresyl (methylphenyl) groups, which makes it a triaryl phosphate ester and, in plastics, a plasticizer and a flame retardant in one molecule. Its synonym tris(methylphenyl) phosphate spells out the structure: one phosphate centre carries three aromatic rings, each with one methyl group, which places TCP at the triaryl end of a range that runs through alkyl diaryl esters such as EHDPP to trialkyl esters such as TEHP.
Which family does a molecule with two jobs belong to? It belongs to both. TCP meets the ASTM D883 definition of a plasticizer, a substance incorporated into a plastic or elastomer to increase its flexibility, workability or distensibility, and its phosphorus adds the flame-retardant role. Phosphate esters are 1 of the 14 chemical classes compared on plasticizers for plastics.
What does TCP stand for, and is it the same as TCPP?#
In plastics, TCP stands for tricresyl phosphate (tritolyl phosphate), and it is not the same substance as TCPP, which is tris(2-chloro-1-methylethyl) phosphate (CAS 13674-84-5), a chlorinated phosphate flame retardant for polyurethane foam. The two names differ by one letter and by one element: TCPP carries chlorine, while the formula of tricresyl phosphate, C21H21O4P, contains none. The 6 phosphate abbreviations that search results mix together are compared below.
| Abbreviation | Full name | CAS | What it is |
|---|---|---|---|
| TCP | tricresyl phosphate | 1330-78-5 | triaryl phosphate flame-retardant plasticizer (this page) |
| TOCP | tri-ortho-cresyl phosphate | see note | the ortho isomer inside TCP |
| TCPP | tris(2-chloro-1-methylethyl) phosphate | 13674-84-5 | chlorinated flame retardant for PU foam |
| TPP (TPHP) | triphenyl phosphate | 115-86-6 | aryl phosphate flame retardant and plasticizer |
| TXP | trixylyl phosphate | 25155-23-1 | xylyl analogue of TCP, SVHC |
| TEP | triethyl phosphate | 78-40-0 | alkyl phosphate flame retardant for PU foam and UPR |
Note: the CAS number of TOCP is not yet verified in our source library, so the cell carries none.
Searches for tricresyl phosphate also return trisodium phosphate and tricalcium phosphate, which are different chemicals and are not plastic additives covered here. The chlorinated foam flame retardant has its own page, TCPP, with its EU toy limit of 5 mg/kg.
Is tricresyl phosphate a single substance or a mixture of isomers?#
Commercial tricresyl phosphate is a mixture of isomers, not a single compound: each of its three cresyl groups can carry its methyl group in the ortho, meta or para position, and CAS 1330-78-5 covers the mixture as sold. The name describes a family of molecules with one formula and one calculated molecular weight, 368.4 g/mol, so a database record for one isomer, such as tri-p-cresyl phosphate, describes one component and not the commercial product.
Isomer composition matters more than the name. The ortho-cresyl isomers are the ones linked to delayed neurotoxicity, so two grades with the same name and the same CAS number can differ in the parameter that decides their hazard, as the safety section below explains.
Is tricresyl phosphate a phthalate or a halogenated flame retardant?#
No on both counts: tricresyl phosphate is a phosphate ester, not an ester of phthalic acid, and its formula C21H21O4P contains no chlorine or bromine, so it is a non-phthalate plasticizer and a halogen-free flame retardant.
In flexible PVC the flame-retardant plasticizers are the phosphate esters (TCP, EHDPP and TEHP) and the chlorinated paraffins, and only the phosphate esters are halogen-free. Phosphate esters sit in the phosphorus group, one of the 6 classes of halogen-free flame retardants.
How Does Tricresyl Phosphate Work in Plastics?#
Tricresyl phosphate works in two ways at once: as a plasticizer it places its ester molecules between the polymer chains and lowers the glass transition temperature, and as a flame retardant it contributes phosphorus, which acts in the burning polymer and in the flame. The 2 roles are listed below.
- Plasticizer role: ester molecules space the polymer chains and raise their mobility.
- Flame-retardant role: phosphorus acts through char in the condensed phase and through flame inhibition in the gas phase.
Which of the two jobs decides the choice? The combination does: a compound that needs only softness takes a general-purpose plasticizer, a compound that needs only fire performance takes a dedicated flame retardant, and TCP earns its place where one additive has to do both.
How does TCP plasticize PVC and cellulosics?#
TCP plasticizes PVC the way every external plasticizer does: its molecules sit between the polymer chains, weaken the van der Waals and dipole forces between them and lower the glass transition temperature of the compound. External plasticizers raise chain mobility without being chemically bound to the polymer, according to European Plasticisers. No solubility parameter, efficiency figure or substitution factor for TCP is recorded in our source library.
Why does a polar aromatic ester suit PVC and cellulose esters? Hallstar's polarity ranking places aromatic phosphates second among plasticizer classes, after aromatic sulfonamides, and compatibility requires the solubility parameters of polymer and plasticizer to lie within ±1.5 (cal/cm3)^0.5. Below about 15 phr a plasticizer stiffens PVC instead of softening it, an effect called antiplasticization. The four plasticization theories, lubricity, gel, free volume and solvation-desolvation, are explained on how plasticizers work.
How does TCP flame-retard a plastic compound?#
TCP flame-retards a compound through its phosphorus: phosphorus flame retardants act in the condensed phase, where they promote char and a glassy inorganic layer, and in the gas phase, where they inhibit the flame, as Bernhard Schartel of BAM set out in the journal Materials in 2010. Which phase dominates for TCP in PVC is not recorded in our source library, so this page assigns no share to either.
The gas-phase route lowers combustion efficiency and raises the carbon monoxide yield of a fire, according to Schartel, and aryl phosphates add a smoke penalty: Hallstar records that aryl groups on a phosphate generate smoke on burning while alkyl groups do not. How the two phases split between red phosphorus, phosphinates and phosphate esters is compared on phosphorus flame retardants.
What Are the Physical and Chemical Properties of Tricresyl Phosphate?#
Tricresyl phosphate has the molecular formula C21H21O4P and a molecular weight of 368.4 g/mol, calculated from that formula for the isomer mixture. Its identifiers, CAS 1330-78-5 and EC 215-548-8, refer to the mixture as sold, and the values verified so far are set out in Table T2.
Table T2. Physical and chemical properties of tricresyl phosphate.
| Property | Value | Source |
|---|---|---|
| Molecular formula | C21H21O4P | PubChem, via our knowledge base |
| Molecular weight | 368.4 g/mol (calculated from the formula) | our knowledge base |
| CAS number | 1330-78-5 (isomer mixture) | PubChem; ECHA CHEM |
| EC number | 215-548-8 | ECHA CHEM |
| Appearance, melting point, boiling point, density, flash point, water solubility | not yet recorded in our source library | none |
Footnote: status as of 24 October 2026. Each constant will be added with one sourced value per property and the source named in the row.
No melting point, boiling point, density, flash point, viscosity or water solubility for tricresyl phosphate is recorded in our source library yet, so this page publishes none.
Which Plastics Use Tricresyl Phosphate, and at What Dosage?#
Tricresyl phosphate is used in 2 groups of plastics, flexible PVC and cellulosics, and its one recorded plastics application is flame-retardant PVC. No typical TCP dosage in phr or wt% is recorded in our source library, so the only number this page can give is the plasticizer range of flexible PVC as a whole, 5 to 65 wt% at Shore A 50 to 90. The two polymer groups are set out in Table T3.
Table T3. Plastics that use tricresyl phosphate.
| Plastic | Role of TCP | Dosage | Source |
|---|---|---|---|
| Flexible PVC | flame-retardant plasticizer | not recorded (flexible PVC total plasticizer content 5 to 65 wt%, Shore A 50 to 90) | our knowledge base |
| Cellulosics | plasticizer with a flame-retardant function | not recorded | our knowledge base |
Footnote: we publish a dosage only where our knowledge base records it.
A PVC compound never consists of resin and plasticizer alone. The stabilizer, lubricant and filler additives for PVC that sit beside the plasticizer are set out in the complete guide to additives for PVC.
Tricresyl phosphate in flexible PVC#
In flexible PVC, tricresyl phosphate is one of the phosphate plasticizers, alongside EHDPP and TEHP, that a compounder uses when the softening agent must also contribute to fire performance. The other route is a chlorinated paraffin, so the choice is between phosphorus and chlorine chemistry. All 12 classes of plasticizers for PVC are compared for hardness, permanence and cost on plasticizers for PVC.
PVC recipes are written in phr, and a figure in PHR (parts per hundred resin) converts to weight percent against the full formulation total: wt% = phr of the ingredient / total phr x 100. As an example of the arithmetic only, not a TCP recipe, 50 phr of plasticizer in a compound with 100 phr PVC is 50 / 150 x 100 = 33.3 wt%.
Fire performance in flexible PVC carries a smoke trade-off. Aryl phosphates generate more smoke than alkyl phosphates, according to Hallstar, so the performance section looks at smoke density as well as at the oxygen index.
Tricresyl phosphate in cellulosic plastics#
Cellulosic plastics are the second polymer group for tricresyl phosphate, because cellulose esters are polar enough to accept an aromatic phosphate ester as a plasticizer. Hallstar's polarity ranking places cellulose acetate above PVC among the polymers, and the sibling aryl phosphate, triphenyl phosphate, is recorded in cellulose acetate film as plasticizer and flame retardant. No individual cellulose ester and no dosage is recorded for TCP in our source library. The plasticizers that suit cellulose acetate and CAB are compared on plasticizers for cellulose acetate and CAB plastics.
How Does Tricresyl Phosphate Perform in Flame-Retardant PVC?#
Aryl phosphate plasticizers such as tricresyl phosphate add fire performance to flexible PVC at a price in smoke: Hallstar's selection guide records that aryl phosphate groups generate smoke on burning while alkyl phosphate groups do not. The same guide records that magnesium hydroxide turns that black smoke white, and plasticizer type in PVC affects the limiting oxygen index of the compound. No limiting oxygen index, UL 94 rating, heat-release value or smoke-density figure for a TCP-plasticized compound is recorded in our source library, so Table T4 names the indicators and their test methods and gives no TCP value.
Table T4. Performance indicators for TCP-plasticized PVC and their test methods.
| Indicator | What our source library records for TCP | Test method |
|---|---|---|
| Ignitability (oxygen demand) | no TCP value; plasticizer type in PVC affects LOI; PVC cable target 26 vol % O2 or higher | ISO 4589-2, ASTM D2863 |
| Smoke | aryl phosphates generate more smoke than alkyl phosphates (class fact) | ASTM E662, ISO 5659-2 (specific optical density Ds) |
| Smoke colour with magnesium hydroxide | black smoke becomes white (class fact) | no standard method recorded |
| Vertical burning | no TCP value | UL 94 (harmonised as IEC 60695-11-10) |
| Plasticizing efficiency | no TCP value | hardness at equal phr against the DEHP reference |
Footnote: class facts describe aryl phosphate plasticizers as a group (Hallstar). A blank TCP value means the value is not in our knowledge base; we do not estimate.
Which fire tests apply to TCP-plasticized PVC?#
Two tests measure the two things TCP is added for in PVC: the limiting oxygen index (ISO 4589-2, ASTM D2863) for how much oxygen a compound needs to keep burning, and smoke density (ASTM E662, ISO 5659-2) for the smoke penalty of an aryl phosphate. The oxygen index is reported in vol % O2, with procedures A, B and C in ASTM D2863-23e1, and typical polymer values are set out under limiting oxygen index (LOI).
PVC cable compounds target an oxygen index of 26 vol % O2 or higher. Huber's reference cable formulation reaches 26 to 27 % with 55 phr DIDP, 45 to 100 phr ATH and 5 phr zinc borate in 100 phr PVC K70, a phosphate-free result that does not transfer to TCP. Smoke density is reported as the specific optical density Ds, and aircraft interiors work to Ds 200 or lower at 4 minutes in the flaming mode of ASTM F814. The method and its limits are explained under smoke density testing.
How does TCP interact with mineral flame retardants and smoke suppressants?#
Mineral flame retardants are the usual partners of a phosphate plasticizer in flame-retardant PVC, and magnesium hydroxide does a second job beside it, turning the black smoke of an aryl phosphate white, according to Hallstar. Phosphate plasticizers are combined with aluminium trihydrate (ATH) or magnesium hydroxide (MDH) in flame-retardant PVC, and ATH and MDH loadings are compared on mineral flame retardants.
ATH releases water from about 200 °C (392 °F) and MDH is stable to about 320 °C (608 °F), according to Huber, which sets the processing window, and zinc borate at 3 to 6 phr reduces smoke and dripping in PVC cable. No synergy value for TCP with these co-additives is recorded in our source library, so these are system facts, not TCP results. Zinc borate and related chemistries are compared as smoke suppressants.
What Is the Regulatory Status of Tricresyl Phosphate?#
Tricresyl phosphate is not a Substance of Very High Concern, not on the REACH Authorisation List, not restricted under REACH Annex XVII, not a persistent organic pollutant and not on the EU Union list for plastic food-contact materials, which makes its EU position lighter than that of its xylyl analogue, trixylyl phosphate. Its CLP classification, its REACH registration and its US status are not yet recorded in our source library, and Table T5 marks those cells.
Table T5. Tricresyl phosphate regulatory status as of 24 October 2026.
| Instrument | TCP status | Date / reference |
|---|---|---|
| REACH registration, Regulation (EC) No 1907/2006 | not yet verified in our source library | ECHA dossier access pending |
| REACH Candidate List (SVHC) | not listed | Candidate List of 253 entries, last updated 4 February 2026 (checked 25 September 2026) |
| REACH Annex XIV (authorisation) | not listed | ECHA CHEM obligation list |
| REACH Annex XVII (restriction) | not listed | ECHA CHEM obligation list |
| EU POPs Regulation (EU) 2019/1021 and Stockholm Convention | not listed | knowledge base regulatory record |
| EU 10/2011 plastic food-contact materials (Union list, Annex I) | not listed | consolidated text of 14 July 2026 |
| CLP Regulation (EC) No 1272/2008 | harmonised classification not recorded in our source library | open verification item |
| EU toy limit for organophosphate flame retardants, Directive 2014/79/EU | TCP not named; the limit covers TCEP, TCPP and TDCP | 5 mg/kg in toys for children under 36 months or intended for the mouth |
| ECHA work on organophosphorus flame retardants | the flame retardants regulatory strategy found that OPFRs need more data; a dedicated investigation with a first report in December 2026 is reported by a secondary source only | ECHA strategy, March 2023 |
| US TSCA | not recorded in our knowledge base | open verification item |
| US FDA food contact (21 CFR) | not recorded in our knowledge base | open verification item |
| California Proposition 65 | not recorded in our knowledge base | open verification item |
| California AB 2998 | covers halogenated and organophosphorus flame retardants above 1,000 ppm in juvenile products, mattresses and upholstered furniture; application to TCP not verified | from 1 January 2020, AB 2998 (2018) |
The REACH registration status of TCP is not yet verified, because ECHA blocked automated access to the registration dossiers during our research pass, so this page says neither "registered" nor "not registered". What registration, the Candidate List and authorisation each require is set out on REACH and plastic additives. The three US cells read "not recorded in our knowledge base" until each list is checked against its primary source.
Is tricresyl phosphate an SVHC under REACH?#
No: tricresyl phosphate is not on the REACH Candidate List of Substances of Very High Concern, which held 253 entries at its last update on 4 February 2026. The status was checked against the ECHA CHEM obligation list on 25 September 2026, and every plastic additive on the SVHC Candidate List is tabulated with its inclusion date and reason.
An article containing TCP therefore triggers none of the duties that apply to listed substances above 0.1 % by weight: the Article 33 communication, the Article 7(2) notification above 1 tonne per year and the SCIP notification required since 5 January 2021. The same is not true of its closest analogue.
Tricresyl phosphate vs trixylyl phosphate: why only one is on the Authorisation List#
Trixylyl phosphate, the phosphate ester with three xylyl groups instead of three cresyl groups, has been a Substance of Very High Concern since 16 December 2013 and has needed an EU authorisation since its sunset date of 27 May 2023, while tricresyl phosphate carries neither listing. Trixylyl phosphate entered the Candidate List as toxic for reproduction under Article 57(c), and Regulation (EU) 2020/171 added it to Annex XIV as entry 47, with a latest application date of 27 November 2021 and no exempted uses recorded.
Table T6. Tricresyl phosphate vs trixylyl phosphate.
| Attribute | Tricresyl phosphate (TCP) | Trixylyl phosphate (TXP) |
|---|---|---|
| Aryl groups | three cresyl (methylphenyl) | three xylyl (dimethylphenyl) |
| CAS number | 1330-78-5 | 25155-23-1 |
| EC number | 215-548-8 | 246-677-8 |
| Candidate List (SVHC) | not listed | 16 December 2013, toxic for reproduction (Art. 57(c)) |
| Annex XIV | not listed | entry 47 (Regulation (EU) 2020/171) |
| Latest application date | not applicable | 27 November 2021 |
| Sunset date | not applicable | 27 May 2023 |
Footnote: status from the ECHA CHEM obligation lists, checked 25 September 2026.
A plasticizer based on trixylyl phosphate cannot be used in the EU after 27 May 2023 without an authorisation, and tricresyl phosphate is not a legal substitute for it by name alone: the two are separate substances with separate CAS numbers, EC numbers and dossiers. Every plastic additive with a sunset date, trixylyl phosphate among them, is listed on the REACH Annex XIV authorisation list.
Is tricresyl phosphate restricted under REACH Annex XVII or the POPs rules?#
No: tricresyl phosphate has no entry in REACH Annex XVII and is not listed under the EU POPs Regulation (EU) 2019/1021 or the Stockholm Convention. The other flame-retardant plasticizer class in PVC, the chlorinated paraffins, carries the POP listings, with MCCP added to Stockholm Convention Annex A at COP-12 in 2025. The entries that do restrict plastic additives are listed under REACH Annex XVII restrictions.
Is tricresyl phosphate allowed in food-contact plastics?#
Not in the EU: tricresyl phosphate is not on the Union list in Annex I of Regulation (EU) No 10/2011 (consolidated text of 14 July 2026), the positive list of additives that may be used in plastic food-contact materials. The alkyl diaryl phosphate EHDPP is on the same list as FCM 392 with a specific migration limit of 2.4 mg/kg, the contrast that matters for a phosphate-plasticizer buyer. FCM numbers and migration limits are explained under the plastic food contact materials regulation.
Our source library records no US food-contact status for tricresyl phosphate, neither a 21 CFR section nor a food contact notification, so no FDA claim is made here in either direction.
What is the US status of tricresyl phosphate?#
Our source library holds no verified US status for tricresyl phosphate under TSCA, the FDA food-contact rules or California Proposition 65, so this page states none until each is checked against the primary list. An absence is printed as "not listed" only after that check. How EPA prioritises, evaluates and restricts additives is explained on TSCA and plastic additives.
California AB 2998 has banned halogenated and organophosphorus flame retardants above 1,000 ppm in juvenile products, mattresses and upholstered furniture since 1 January 2020; whether TCP falls under its definition in a given product is not verified here. The aryl phosphate that a federal rule does name is PIP (3:1): under the TSCA section 6(h) rule for persistent, bioaccumulative and toxic chemicals, 40 CFR 751.407, the distribution of most articles containing it is prohibited after 31 October 2026. Furniture standards and state bans are collected under flame retardant regulations.
Is Tricresyl Phosphate Safe? Ortho-Cresyl Isomers, Health and Hazard Classification#
The health hazard of tricresyl phosphate is tied to its ortho-cresyl isomers: neurotoxicity, specifically organophosphate-induced delayed neuropathy (OPIDN), is linked to those isomers, which is why commercial grades are made to minimise their content. The safety question for a plastics buyer is therefore a question about grade composition, not only about the substance name.
No harmonised CLP classification and no GHS hazard statement for tricresyl phosphate is recorded in our source library yet, so this page states none. How harmonised and self-classifications differ is explained under CLP classification of plastic additives.
For the same reason this page makes neither an unqualified "safe" claim nor an unqualified "toxic" claim: both would ignore the isomer composition that decides the hazard.
Exposure, dose and the wider health evidence belong on a dedicated page. Exposure and health evidence across flame-retardant classes is assessed on flame retardants and human health.
What is TOCP (tri-ortho-cresyl phosphate)?#
TOCP, tri-ortho-cresyl phosphate, is the isomer of tricresyl phosphate in which all three cresyl groups carry their methyl group in the ortho position, next to the oxygen that links the ring to phosphorus. TCP names the commercial mixture, and TOCP names one defined member of it.
TOCP is therefore not a synonym for commercial TCP. The neurotoxicity is linked to the ortho-cresyl isomers as a group, so a grade's total ortho-cresyl content, not only its TOCP content, is the number a buyer needs. The CAS number of TOCP is not yet verified in our source library and is not printed here.
Why are commercial TCP grades low in ortho-cresyl isomers?#
Commercial tricresyl phosphate grades are made with as little ortho-cresyl content as possible, because the delayed neurotoxicity of the substance is linked to the ortho-cresyl isomers. Ortho-cresyl content is therefore the specification that separates one TCP grade from another on hazard, while the name, the CAS number and the formula stay the same. No maximum ortho-cresyl content and no grade threshold is recorded in our source library, so this page quotes none.
A buyer should ask for the ortho-cresyl isomer content on the specification and on each certificate of analysis, because a name or a CAS number alone does not state it.
What Are the Alternatives to Tricresyl Phosphate?#
The 5 alternatives to tricresyl phosphate fall into 2 groups: other phosphate esters (EHDPP, triphenyl phosphate, RDP and TEHP) and the chlorinated paraffins, and the choice between them turns on food-contact listing, SVHC status and smoke. Our knowledge base records EHDPP and RDP as the alternatives to TCP, and triphenyl phosphate, TEHP and MCCP complete the comparison in Table T7.
Table T7. Tricresyl phosphate and its alternatives compared.
| Additive | CAS | Class | Main plastics use | SVHC | Annex XIV / XVII | EU 10/2011 | POPs |
|---|---|---|---|---|---|---|---|
| Tricresyl phosphate (TCP) | 1330-78-5 | triaryl phosphate | flame-retardant plasticizer, PVC and cellulosics | no | no / no | not listed | no |
| EHDPP | 1241-94-7 | alkyl diaryl phosphate | flame-retardant plasticizer, PVC including food-packaging PVC | no | no / no | FCM 392, SML 2.4 mg/kg | no |
| Triphenyl phosphate (TPP) | 115-86-6 | aryl phosphate | flame retardant and plasticizer: PC/ABS, PPE/HIPS, PVC, cellulose acetate film | yes, 7 Nov 2024 (endocrine disruption, environment, Art. 57(f)) | not listed, proposed 2 Feb 2026 / not recorded | not recorded | not recorded |
| RDP | 57583-54-7 (monomer); 125997-21-9 (oligomer) | aryl oligophosphate | halogen-free flame retardant, PC/ABS and PPE/HIPS | no | not recorded | not recorded | not recorded |
| TEHP | 78-42-2 | trialkyl phosphate | low-temperature flame-retardant plasticizer, PVC and rubber | no | no / no | not listed | no |
| MCCP | 85535-85-9 | chlorinated paraffin (C14-17) | secondary plasticizer and flame retardant, PVC cable | yes, 8 Jul 2021 (PBT, vPvB) | no / not recorded | not listed | Stockholm Annex A (COP-12, 2025); EU act adopted, not yet published in the OJ |
Footnote: "not recorded" means the value is not in our knowledge base; we do not estimate. RDP is an alternative in the flame-retardant role in engineering plastics, not a PVC plasticizer. Status as of 24 October 2026.
EHDPP is the only substance in the table with a confirmed Union list entry, triphenyl phosphate is the only phosphate on the Candidate List (since 7 November 2024), and MCCP is both an SVHC and a newly listed POP. RDP is an alternative only in the flame-retardant role, as an aryl oligophosphate for PC/ABS and PPE/HIPS housings, and the oligomeric aryl phosphate is profiled under RDP (resorcinol bis(diphenyl phosphate)).
Tricresyl phosphate vs EHDPP (2-ethylhexyl diphenyl phosphate)#
EHDPP is the phosphate plasticizer to choose over tricresyl phosphate when a flexible PVC article must meet EU food-contact rules, because EHDPP is on the Union list as FCM 392 with a specific migration limit of 2.4 mg/kg and TCP is not on the list at all. EHDPP replaces one of the three aryl groups with a 2-ethylhexyl group, and Hallstar links aryl groups, not alkyl groups, to smoke, so the structural difference between the two esters sits in the group the class data tie to smoke. Its identity record and food-contact limits are set out on 2-ethylhexyl diphenyl phosphate.
Tricresyl phosphate vs triphenyl phosphate and RDP#
Triphenyl phosphate is the closest chemical relative of tricresyl phosphate, the same triaryl phosphate without the methyl groups, but since 7 November 2024 it has been a Substance of Very High Concern, so switching from TCP to TPP adds an EU listing rather than removing one. TPP (CAS 115-86-6, 326.3 g/mol) is listed for endocrine-disrupting properties for the environment, and ECHA's draft 13th Annex XIV recommendation of 2 February 2026 proposes it for authorisation. Its Candidate List entry and its TSCA status are detailed on the triphenyl phosphate page.
RDP, resorcinol bis(diphenyl phosphate), is the oligomeric aryl phosphate: a liquid halogen-free flame retardant for PC/ABS and PPE/HIPS housings that is not an SVHC, which is why it replaces TCP only in the flame-retardant role.
Tricresyl phosphate vs chlorinated paraffins in flame-retardant PVC#
Chlorinated paraffins are the other flame-retardant plasticizer class in PVC, and they now carry heavier listings than tricresyl phosphate: SCCP is a persistent organic pollutant, and MCCP has been an SVHC since 8 July 2021 and was added to the Stockholm Convention in 2025. SCCP has been in Stockholm Annex A since COP-8 in 2017 (decision SC-8/11) and is prohibited in the EU, while the EU act for MCCP, Commission Delegated Regulation C(2026) 6262 of 11 September 2026, is adopted by the Commission but not yet published in the Official Journal. Chlorinated paraffins work with antimony oxide as a flame-retardant synergist, according to Hallstar, while TCP brings phosphorus and no halogen. The SCCP, MCCP and LCCP chain-length classes are explained under chlorinated paraffins.
Who Supplies Tricresyl Phosphate? Grades, Price and Sourcing#
Our source library does not yet record which companies produce tricresyl phosphate or under which trade names, so this page lists none and instead sets out the 5 documents a buyer needs before a first order. Producers of phosphate and other plasticizers are listed by region in the directory of plasticizer manufacturers.
No tricresyl phosphate price is recorded in our source library; quotes depend on the grade, the ortho-isomer specification, the volume and the delivery terms. Buyers should ask for the ortho-cresyl isomer content in writing, because it is the single specification that separates one TCP grade from another on hazard. The 5 documents are set out in Table T8.
Table T8. What to request from a tricresyl phosphate supplier.
| Document | What to check | Why |
|---|---|---|
| Safety data sheet | CAS 1330-78-5 and EC 215-548-8, hazard section | confirms the substance is the isomer mixture, not a single isomer |
| Specification sheet | ortho-cresyl isomer content (maximum) | the hazard is linked to the ortho-cresyl isomers |
| Certificate of analysis (per batch) | measured ortho-cresyl content | batch-to-batch control of the same parameter |
| REACH statement | registration number and tonnage band of the importer or producer | TCP's registration status is not verified in our source library |
| Food-contact statement | confirmation that the article is not for EU food contact | TCP is not on the EU 10/2011 Union list |
Footnote: no supplier is named because our knowledge base does not yet record one; see our methodology.
TCP is sold as a flame retardant as well as a plasticizer, so its producers can sit in either supplier directory. Organophosphate flame retardant producers are covered in the directory of flame retardant manufacturers.
How Does Tricresyl Phosphate Fit into the Phosphate Ester Plasticizer Family?#
Tricresyl phosphate is the triaryl member of the phosphate ester plasticizers, the class of phosphoric acid esters that soften a polymer and add phosphorus to it, and that sits in two additive families at once. In European usage the class is written phosphate plasticisers, and more than 85 % of all plasticiser use in Europe goes into flexible PVC, according to European Plasticisers. Smoke, oxygen-index and food-contact data for the whole class are compared on phosphate ester plasticizers.
The plasticizer view and the fire view describe the same molecules. Seen from the fire side, the same molecules are grouped as organophosphate flame retardants, the class that ECHA's flame retardants regulatory strategy of March 2023 found to need more data.
Aryl, alkyl-aryl and alkyl phosphate plasticizers#
Phosphate ester plasticizers split into 3 groups by what sits on the phosphate: aryl groups (triaryl phosphates such as TCP), a mix of alkyl and aryl groups (alkyl diaryl phosphates such as EHDPP) and alkyl groups only (trialkyl phosphates such as TEHP). The 6 phosphate esters closest to TCP in plastics are listed below.
- EHDPP (2-ethylhexyl diphenyl phosphate): alkyl diaryl phosphate, flame-retardant plasticizer for PVC and food-packaging PVC.
- IDDP (isodecyl diphenyl phosphate): alkyl diaryl phosphate flame-retardant plasticizer, CAS 29761-21-5, registered under REACH at 100 to 1,000 tonnes per year.
- BPDP (tert-butylphenyl diphenyl phosphate): triaryl phosphate reaction mass, EC 700-990-0, flame-retardant plasticizer.
- PIP (3:1): aryl phosphate UVCB under the TSCA PBT rule, profiled as PIP (3:1) (isopropylated triphenyl phosphate).
- TEHP: trialkyl phosphate for low-temperature flame-retardant PVC and rubber, profiled as TEHP (tris(2-ethylhexyl) phosphate).
- TEP: alkyl phosphate flame retardant for PU foam and UPR, profiled as triethyl phosphate.
Moving from the triaryl end of this list toward the trialkyl end replaces aromatic rings with alkyl chains, the structural change Hallstar ties to lower smoke.
Non-plastics uses of tricresyl phosphate: lubricants and lacquers#
Outside plastics, tricresyl phosphate is used as an anti-wear additive in lubricants and in lacquers, two uses this reference does not cover because they fall outside plastics. Lubricant additives and coatings follow their own technical and regulatory rules, so neither use is described further here.
Is tricresyl phosphate banned?#
No: tricresyl phosphate is not banned or restricted under any EU instrument in our source library (REACH Annex XIV and XVII, the POPs Regulation), although it is not authorised for EU plastic food-contact materials because it is not on the Union list (status 24 October 2026). Its US status is not yet verified, so no statement about a US ban or restriction is made here.
Does tricresyl phosphate migrate out of PVC?#
Tricresyl phosphate is an external plasticizer, held between the PVC chains rather than bonded to them, so like every external plasticizer it can migrate, but no TCP migration or volatility value is recorded in our source library. The causes and the test routes are explained under additive migration in plastics.
Is tricresyl phosphate used in food packaging?#
Not in the EU: tricresyl phosphate is not on the Union list of Regulation (EU) No 10/2011 (consolidated text of 14 July 2026), so it is not an authorised additive for plastic food packaging, unlike EHDPP (FCM 392). For EU food packaging made from flexible PVC, the listed phosphate option is EHDPP, with a specific migration limit of 2.4 mg/kg.