Registration Dossier

Administrative data

sensitisation data (humans)
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
No data
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Meets generally accepted scientific standards with acceptable restrictions. This study is conducted on an analogue substance. Read-across is justified on the following basis: In aqueous solutions at physiological and acidic pH, low concentrations of simple inorganic borates such as boric acid, disodium tetraborate decahydrate, disodium tetraborate pentahydrate, boric oxide and disodium octaborate tetrahydrate will predominantly exist as undissociated boric acid. At about pH 10 the metaborate anion (B(OH)4-) becomes the main species in solution (WHO, 1998). This leads to the conclusion that the main species in the plasma of mammals and in the environment is un-dissociated boric acid. Since other borates dissociate to form boric acid in aqueous solutions, they too can be considered to exist as un-dissociated boric acid under the same conditions. For comparative purposes, exposures to borates are often expressed in terms of boron (B) equivalents based on the fraction of boron in the source substance on a molecular weight basis. Some studies express dose in terms of B, whereas other studies express the dose in units of boric acid. Since the systemic effects and some of the local effects can be traced back to boric acid, results from one substance can be transferred to also evaluate the another substance on the basis of boron equivalents. Therefore data obtained from studies with these borates can be read across in the human health assessment for each individual substance. Conversion factors are given in the table below. Conversion factor for equivalent dose of B Boric acid H3BO3 0.175 Boric Oxide B2O3 0.311 Disodium tetraborate anhydrous Na2B4O7 0.215 Disodium tetraborate pentahydrate Na2B4O7•5H2O 0.148 Disodium tetraborate decahydrate Na2B4O7•10H2O 0.113 Disodium octaborate tetrahydrate Na2B8O13•4H2O 0.210 Sodium metaborate (anhydrous) NaBO2 0.1643 Sodium metaborate (dihydrate) NaBO2•2H2O 0.1062 Sodium metaborate (tetrahydrate) NaBO2•4H2O 0.0784 Sodium pentaborate (anhydrous) NaB5O8 0.2636 Sodium pentaborate (pentahydrate) NaB5O8∙5H2O 0.1832 References: WHO. Guidelines for drinking-water quality, Addendum to Volume 1, 1998.

Data source

Reference Type:
Occupational contact dermatitis from alkanolamine borates in metalworking fluids.
Bruze, M, Hradil, E, Erikson I-L, Gruvberger B and Widstrom
Bibliographic source:
Contact Dermatitis 32: 24 - 27.

Materials and methods

Type of sensitisation studied:
Study type:
other: Three patients; no other data.
Test guideline
according to guideline
other: No data
not specified
Principles of method if other than guideline:
Three patients were patch tested. Case No 1: Al-test, Astra Agency, Sweden with 25 µL of test agent. Case 2 & 3 ; Finn Chamber, Epicon OY, Finland with 15 µL of test agent.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Boric acid
EC Number:
EC Name:
Boric acid
Cas Number:
Molecular formula:
Boric acid
Details on test material:
- Name of test material: Boric acid tested at 3 % w/v.


Type of population:
not specified
No data
Route of administration:

Results and discussion

Results of examinations:
Not sensitising.

Applicant's summary and conclusion

Boric acid tested at 3 % w/v in water showed no sensitisation in a patch test on three patients.
Read-across is justified on the basis detailed in the rationale for reliability above. This study is therefore considered to be of sufficient adequacy and reliability to be used as a supporting study and no further testing is justified.