# Boron oxide (B2O3)

URL: https://app.greenveil.ai/ingredients/ingredient_cas_1303_86_2
Categories: beauty, cleaning, industrial, pharma
Functions: Chemical reaction regulator, glaze, Stabilizing agent
Identifier: 1303-86-2

> Boron oxide (B2O3) is used as chemical reaction regulator / glaze. Greenveil chemical-concern score: 100/100 — Critical concern driven by cmr.. Assessed from 7 sources.

## Safety assessment

- Chemical concern score: 100/100 — Critical concern driven by cmr.
- Confidence: 4
- Rationale: Diboron trioxide; boric oxide is prohibited in cosmetic products under Annex II of the EU Cosmetics Regulation (EC) 1223/2009.

## Regulatory status

- EU: banned — Annex II of EU Cosmetics Regulation (EC) 1223/2009: substances prohibited in cosmetic products. CMR: Reprotoxic Cat. 1B()
- US: commercial use observed — EPA CPDat observed this chemical in 726 composition records across product categories including Furniture and furnishings, Specialty occupational products, Laboratory supplies. EPA CPDat classifies this chemical for functional uses including glaze, Chemical reaction regulator, Stabilizing agent.
- US: marketed drug occurrence — FDA NDC lists this ingredient in 9 active drug products and 9 total products.
- US: listed in openFDA substance — openFDA substance registry classifies this ingredient as chemical.

_Assessed by Greenveil._