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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Sensitisation data (human)

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Administrative data

sensitisation data (humans)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The EU RAR reviews the available literature.

Data source

Reference Type:
review article or handbook
European Union Risk Assessment Report: chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate and potassium dichromate
European Chemicals Bureau
Bibliographic source:
3rd. Priority List; Volume 53

Materials and methods

Type of sensitisation studied:
Study type:
other: EU RAR review of available data
Test guideline
no guideline followed
Principles of method if other than guideline:
Reports of clinical cases and patch-testing studies of various designs.
GLP compliance:
Not applicable

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium dichromate
EC Number:
EC Name:
Sodium dichromate
Cas Number:
Molecular formula:
sodium dichromate
Constituent 2
Chemical structure
Reference substance name:
Potassium dichromate
EC Number:
EC Name:
Potassium dichromate
Cas Number:
Molecular formula:
potassium dichromate
Details on test material:
The EU RAR covers the water soluble Cr (VI) compounds chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate and
potassium dichromate. Patch testing was carried out mainly using sodium or potassium dichromate, however the results can be qualitatively
extrapolated to the other compounds in this group.


Type of population:
other: general and occupational
Not reported.
Route of administration:

Results and discussion

Results of examinations:
See discussion below.

Any other information on results incl. tables

Concentrations of 0.5% and below of aqueous potassium dichromate have been reported to elicit positive responses in patch testing studies. In one study, a minimum (10% reacting) elicitation concentration of 0.09 μg Cr(VI)/cm² was calculated after 54 Cr(VI)-sensitive volunteers were exposed to potassium dichromate.

Applicant's summary and conclusion

The results of patch testing studies reported in the EU RAR indicate that the water-soluble Cr (VI) compounds in this group are capable of causing skin sensitisation following occupational exposure.
Executive summary:

Allergic contact dermatitis (skin sensitisation) resulting from occupational exposure to water soluble Cr (VI) compounds is commonly encountered in a number of different groups. The EU RAR has reviewed a number of published reports of patch testing in Cr (VI) sensitised humans; the studies report minimum eliciting concentrations as low as 0.09 ug Cr (VI) /cm². The majority of reported studies were performed using aqueous solutions of sodium or potassium dichromate; while similar effects can be assumed for other water-soluble Cr (VI) compounds, a similar concentration-response relationship cannot be assumed as this will also be influenced by the extent of dermal penetration.