Baby Safety / Compounds / Iodine-131 (¹³¹I)

Is Iodine-131 (¹³¹I) safe for babies and kids?

Extreme risk for kids

Infants are more vulnerable to Iodine-131 (¹³¹I) than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

What is iodine-131 (¹³¹i)?

The IUPAC name is iodane.

Also known as: iodane, 131I, (131I)iodanyl, I-131 radioisotope.

IUPAC name
iodane
CAS number
10043-66-0
Molecular formula
I
Molecular weight
130.906126 g/mol
SMILES
I
PubChem CID
5489939

Risk for babies

Extreme risk

Infants are more vulnerable to Iodine-131 (¹³¹I) than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

Neonates and infants up to 12 months have incomplete blood-brain barrier development, immature Phase I/II metabolic enzymes (particularly CYP3A4, UGT1A1), and higher gastrointestinal permeability. Equivalent doses produce higher internal concentrations and longer residence times.

What to do: Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

Risk for pregnant and nursing people

Severe risk

Pregnancy alters the metabolism and distribution of Iodine-131 (¹³¹I), potentially increasing fetal exposure. The developing embryo/fetus is vulnerable during organogenesis (weeks 3-8) and neurological development. Placental transfer should be assumed.

Known reproductive toxicant (GHS H360) or confirmed endocrine disruptor. Placental transfer is presumed. Fetal exposure during critical developmental windows may cause structural malformations, growth restriction, or functional deficits.

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

Regulatory consensus

1 regulatory bodyhas classified Iodine-131 (¹³¹I).

AgencyYearClassificationNotes
IARC—Group 1ionizing radiation classified as Group 1

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 iodine-131 (¹³¹i)

  • 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 Iodine-131 (¹³¹I):

  • Shielding / distance / time (radiation protection)
    Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
    Relative cost: 1.2-2×

Frequently asked questions

Is iodine-131 (¹³¹i) safe for kids?

Infants are more vulnerable to Iodine-131 (¹³¹I) than children or adults due to immature hepatic/renal clearance, higher intake-to-body-weight ratio, rapid organ development, and increased gastrointestinal absorption.

What products contain iodine-131 (¹³¹i)?

Iodine-131 (¹³¹I) appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments).

What should I do if my child is exposed to iodine-131 (¹³¹i)?

Minimize infant exposure through source control. For breastfeeding mothers: reduce maternal exposure. For formula-fed infants: use certified low-migration bottles and verified water sources. Consult pediatrician regarding any concerns.

See Iodine-131 (¹³¹I) in the baby app

Look up products containing iodine-131 (¹³¹i), compare to alternatives, and explore the full data record.

Open in baby View raw API data

Sources (3)
  1. WHO: Chernobyl — Iodine-131 Release and Childhood Thyroid Cancer, 6,000+ Post-Accident Cases in Belarus/Ukraine, Milk Contamination Pathway, Potassium Iodide Distribution Failure, and 20-Year Follow-Up of Thyroid Cancer Cohort (2006) (2006) — regulatory
  2. US NRC: Iodine-131 Fact Sheet — 8.02-Day Half-Life, Thyroid-Specific Accumulation, Medical Use (Thyroid Ablation), Environmental Release (Nuclear Accidents), and Potassium Iodide Thyroid Blocking Mechanism (2020) (2020) — regulatory
  3. US FDA: Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies — Recommended Doses by Age Group, Efficacy Against Radioiodine, Contraindications, and Pre-Positioning Within 10-Mile Nuclear Power Plant Emergency Planning Zones (2001) (2001) — 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 →