Registration Dossier

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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Administrative data

repeated dose toxicity: inhalation
other: Assessment
Type of information:
other: Expert Assessment
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Expert Assessment as opposed to experimental result

Data source

Reference Type:
other: Expert Assessment
Report date:

Materials and methods

Principles of method if other than guideline:
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide
EC Number:
EC Name:
Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide
Cas Number:
Molecular formula:
Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide
Silicic acid (H4SiO4), zirconium(4+) salt (1:1), reaction products with sodium hydroxide

Results and discussion

Effect levels

Remarks on result:
not measured/tested
The substance has a pH of around 12. The high pH makes repeated dose toxicity (oral) inappropriate for animal welfare reasons.

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables


Applicant's summary and conclusion

Executive summary:

This substance is the product of a reaction between Zircon (EC no 239-019-6) and sodium hydroxide. The substance in water has a pH of >13; it is non-volatile, but is prone to dusting. The high pH makes testing by the inhalation route inappropriate for animal welfare reasons. In addition, REACH Annex VIII requires testing by “the most appropriate route of exposure” where testing additional to the oral route is appropriate. As well as animal welfare considerations, testing by the inhalation route would be inappropriate as the severe irritancy affect would mask any systemic toxicity effects. Furthermore, the wealth of data for zirconium salts and silicates indicates a low order of chronic toxicity. Toxicity of this substance by the oral route has been assessed. An LD50 of approximately 1300 mg/kg has been established. This further supports the assertion of low systemic toxicity. In addition, an inhalation toxicity study has been conducted for silicic acid, potassium salt (215-199-1), which showed an LC50 of >2.06 mg/L air. Thus, running an acute inhalation study would add nothing to the hazard assessment for this substance, and risk management measures are driven primarily by its corrosive nature due to the high pH. Determination of acute toxicity by the inhalation route is therefore considered inappropriate and unnecessary.

The above should be considered as an expert statement to waive the requirement for testing for acute toxicity by the inhalation route REACH Annex VIII for endpoint 8.6.1.