Baby Safety / Compounds / 3,3'-Dimethylbenzidine (ortho-tolidine)

Is 3,3'-Dimethylbenzidine (ortho-tolidine) safe for babies and kids?

Context-dependent for kids

(Babies-specific data is limited; this page draws from human pregnant context.) Pregnancy alters the metabolism and distribution of 3,3'-Dimethylbenzidine (ortho-tolidine), potentially increasing fetal exposure. The developing embryo/fetus is vulnerable during organogenesis (weeks 3-8) and neurological development. Placental transfer should be assumed.

What is 3,3'-dimethylbenzidine (ortho-tolidine)?

The IUPAC name is 4-(4-amino-3-methylphenyl)-2-methylaniline.

Also known as: 4-(4-amino-3-methylphenyl)-2-methylaniline, o-Tolidine, 3,3'-DIMETHYLBENZIDINE, Orthotolidine.

IUPAC name
4-(4-amino-3-methylphenyl)-2-methylaniline
CAS number
119-93-7
Molecular formula
C14H16N2
Molecular weight
212.29 g/mol
SMILES
CC1=C(C=CC(=C1)C2=CC(=C(C=C2)N)C)N
PubChem CID
8413

Risk for babies

Context-dependent

Pregnancy alters the metabolism and distribution of 3,3'-Dimethylbenzidine (ortho-tolidine), potentially increasing fetal exposure. The developing embryo/fetus is vulnerable during organogenesis (weeks 3-8) and neurological development. Placental transfer should be assumed.

No specific reproductive toxicity data identified, but pregnancy-specific safety data is limited for most chemicals. Precautionary minimization of exposure is recommended.

What to do: Minimize exposure during pregnancy and lactation. Consult healthcare provider regarding specific risks. Consider alternative products with lower hazard profiles.

Risk for pregnant and nursing people

Context-dependent

Pregnancy alters the metabolism and distribution of 3,3'-Dimethylbenzidine (ortho-tolidine), potentially increasing fetal exposure. The developing embryo/fetus is vulnerable during organogenesis (weeks 3-8) and neurological development. Placental transfer should be assumed.

No specific reproductive toxicity data identified, but pregnancy-specific safety data is limited for most chemicals. Precautionary minimization of exposure is recommended.

What to do: Minimize exposure during pregnancy and lactation. Consult healthcare provider regarding specific risks. Consider alternative products with lower hazard profiles.

Regulatory consensus

11 regulatory and scientific bodies have classified 3,3'-Dimethylbenzidine (ortho-tolidine). The classifications differ — that's the data.

AgencyYearClassificationNotes
IARC1972Group 2B
US EPA2000probable human carcinogen (Group B2)
EPA CTX / NIOSH—potential occupational carcinogen
EPA CTX / NTP RoC—Reasonably Anticipated to be a Human Carcinogen
EPA CTX / IARC—Group 2B - Possibly carcinogenic to humans
EPA CTX / CalEPA—Known human carcinogen
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 13 positive / 2 negative reports)
EPA CTX / Genetox—Genotoxicity: positive (Ames: positive, 13 positive / 2 negative reports)
EPA CTX / Skin-Eye—Skin Irritation: Not classified (score: low)
EPA CTX / Skin-Eye—Eye Irritation: Category 6.4A (Category 2A) (score: high)
EPA CTX / Skin-Eye—Skin Irritation: Category 6.3B (Category 3) (score: moderate)

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 kids encounter 3,3'-dimethylbenzidine (ortho-tolidine)

  • Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
  • Occupational Environments — Factories, Warehouses, Transportation vehicles

Safer alternatives

Lower-risk approaches that achieve a similar outcome to 3,3'-Dimethylbenzidine (ortho-tolidine):

  • DPD (N,N-diethyl-p-phenylenediamine) method
    Trade-offs: Slightly less stable reagent. Narrower linear range. Requires spectrophotometer for precision.
    Relative cost: 1.2×
  • Digital colorimeter with pre-filled reagent vials
    Trade-offs: Higher equipment cost. Better accuracy and reproducibility.
    Relative cost: Equipment $200-400; reagents similar

Frequently asked questions

What products contain 3,3'-dimethylbenzidine (ortho-tolidine)?

3,3'-Dimethylbenzidine (ortho-tolidine) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).

Why do regulators disagree about 3,3'-dimethylbenzidine (ortho-tolidine)?

3,3'-Dimethylbenzidine (ortho-tolidine) has been classified by 11 agencies including IARC, US EPA, EPA CTX / NIOSH, EPA CTX / NTP RoC, EPA CTX / IARC, with differing conclusions. 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. See the regulatory consensus table on this page for the full picture.

See 3,3'-Dimethylbenzidine (ortho-tolidine) in the baby app

Look up products containing 3,3'-dimethylbenzidine (ortho-tolidine), compare to alternatives, and explore the full data record.

Open in baby View raw API data

Sources (2)
  1. IARC Monographs Volume 1: Some Inorganic Substances, Chlorinated Hydrocarbons, Aromatic Amines — 3,3'-Dimethylbenzidine Group 2B; Bladder and Zymbal's Gland Tumors; Benzidine Structural Analog; OSHA 29 CFR 1910.1006; Pool Chlorine Test Kit Historical Use (1972) — iarc_monograph
  2. US EPA o-Tolidine Assessment: Group B2 Probable Carcinogen; DPD Replacement of Pool Test Kits; Polyurethane Chain Extender; Azo Dye Precursor; Dermal Exposure in Pool Operators; Cancer Slope Factor Established (2000) — 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 →