Boric acid

CAS 10043-35-3 · EC 233-139-2 · BH3O3

Handle chemistry safely

Wear gloves and eye protection, work with good ventilation, and read the supplier’s safety data sheet before use. Hazard information here is a summary, not a replacement for it. Dispose of all photographic chemistry correctly, in line with local laws and your local authority’s guidance. Never mix waste solutions, and check the supplier’s safety data sheet before disposing of anything.

Hazards

Official EU classification (harmonised under CLP Annex VI).

Signal word: Danger

Serious health hazard

H360FD May damage fertility. May damage the unborn child.

UK and EU rules

CLP Annex VI Repr. 1B (H360FD) – harmonised entry 005-007-00-2 (ATP20)
REACH Candidate List (SVHC) – ECHA CHEM shows an indirect (group) entry

Photographic uses

buffer in hardening fixer (F-5)

Used in: Kodak F-5 acid hardening fixer

Sources

ECHA CHEM substance record: Boric acid (100.030.114)
ECHA CHEM – C&L Inventory (harmonised CLP Annex VI and notified classifications) and legal obligations (chem.echa.europa.eu APIs: /api-cnl-inventory/harmonized|industry, /api-obligation-substance/v1)
REACH Annex XVII entries 28–30 (CMR substances – supply to general public) (Annex XVII entries 28, 29, 30; latest consolidated act CELEX 32025R1731)

Checked October 2026.