Food & Drink / Compounds / Diisooctyl phthalate (DIOP)

Diisooctyl phthalate (DIOP) in food: ingestion safety

Low risk

(People-specific data is limited; this page draws from human adult context.) Diisooctyl phthalate (DIOP; CAS 27554-26-3) presents a low risk to human adults at current exposure levels. DIOP's declining industrial use limits population-level dietary and environmental exposure. No individual US EPA IRIS RfD or EFSA TDI has been established for DIOP, making formal margin-of-exposure calculations impossible. Risk extrapolation from DEHP class data suggests that DIOP mono-ester metabolites may exhibit anti-androgenic activity at high doses, but ambient exposure levels are expected to be substantially below effect thresholds given DIOP's limited current use. Human biomonitoring data for DIOP-specific metabolites are limited. Risk assessment relies on structural class considerations.

What is diisooctyl phthalate (diop)?

The IUPAC name is bis(6-methylheptyl) benzene-1,2-dicarboxylate.

Also known as: bis(6-methylheptyl) benzene-1,2-dicarboxylate, Diisooctyl phthalate, Isooctyl phthalate, Diop.

IUPAC name
bis(6-methylheptyl) benzene-1,2-dicarboxylate
CAS number
27554-26-3
Molecular formula
C24H38O4
Molecular weight
390.6 g/mol
SMILES
CC(C)CCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCC(C)C
PubChem CID
33934

Risk for people

Low risk

Diisooctyl phthalate (DIOP; CAS 27554-26-3) presents a low risk to human adults at current exposure levels. DIOP's declining industrial use limits population-level dietary and environmental exposure. No individual US EPA IRIS RfD or EFSA TDI has been established for DIOP, making formal margin-of-exposure calculations impossible. Risk extrapolation from DEHP class data suggests that DIOP mono-ester metabolites may exhibit anti-androgenic activity at high doses, but ambient exposure levels are expected to be substantially below effect thresholds given DIOP's limited current use. Human biomonitoring data for DIOP-specific metabolites are limited. Risk assessment relies on structural class considerations.

Regulatory consensus

1 regulatory bodyhas classified Diisooctyl phthalate (DIOP).

AgencyYearClassificationNotes
US EPA / ECHA (DIOP — diisooctyl phthalate — CAS 27554-26-3; limited individual regulatory assessment; structurally related to DEHP (both C8 phthalates) but with different branching pattern affecting metabolic activation; anti-androgenic phthalate class effects expected but species-specific and dose-dependent; no individual IRIS assessment; no ECHA SVHC listing as individual compound; not classified for carcinogenicity by IARC, NTP, EFSA, or US EPA; use declining in favor of higher-MW phthalates and non-phthalate alternatives)2020no carcinogenicity classification; C8 branched phthalate plasticizer; anti-androgenic activity expected from class; limited individual regulatory assessment; not classified by IARC, NTP, EFSA, or US EPA for carcinogenicity

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter diisooctyl phthalate (diop)

  • Consumer Products — Plastic bottles and containers, Food packaging, Plastic toys and household items
  • Drinking Water — Leaching from plastic pipes, Migration from bottled water containers
  • Indoor Environments — Off-gassing from plastic furniture, Degradation of plastic products

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Diisooctyl phthalate (DIOP):

  • Fragrance-free formulations
    Trade-offs: Consumer preference for scented products
    Relative cost: Lower (ingredient elimination)
  • Essential oil-based fragrances (with disclosure)
    Trade-offs: Natural does not mean safe — many essential oils are skin sensitizers
    Relative cost: 2-5× conventional

Frequently asked questions

What products contain diisooctyl phthalate (diop)?

Diisooctyl phthalate (DIOP) appears in: Plastic bottles and containers (Consumer products); Food packaging (Consumer products); Leaching from plastic pipes (Drinking water); Migration from bottled water containers (Drinking water); Off-gassing from plastic furniture (Indoor environments).

See Diisooctyl phthalate (DIOP) in the food app

Look up products containing diisooctyl phthalate (diop), compare to alternatives, and explore the full data record.

Open in food View raw API data

Sources (1)
  1. US EPA ECHA DIOP Diisooctyl Phthalate CAS 27554-26-3; C8 Branched Phthalate DEHP Structural Relative; Limited Individual Regulatory Assessment; Anti-Androgenic Class Effects Expected; No IRIS RfD; No SVHC Listing; No IARC NTP EFSA EPA Carcinogenicity Classification (2020) — regulatory

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →