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Toxicological information

Acute Toxicity: inhalation

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Administrative data

acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Test carried out by GLP compliant laboratory to recognised validated methods by trained personnel

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
no guideline available
Principles of method if other than guideline:
Twenty rats (10 male, 10 female) were weighed and checked for health issues and acclimatised in a holding room prior to test initiation. They were housed in controlled humidity and temperature conditions. Ten rats were used for the substance exposure and 10 rats used for the control (clean air). Each rat was placed in individual compartments within a 0.13 cubic meter perspex chamber. Air flow was 25l/min (measured at the generator outlet)and the test material in powder form was introduced via this air stream for a period of 4 hours following a 12 minute equilibration period. The air was sampled 5 times during the 4 hour period and the particle size of the dust was also measured. After exposure the rats were returned to their cage and observed for signs of pharmacotoxic effects and mortality continuously after exposure and then at least twice daily for 14 days. After this time the rats were euthenased and subjected to gross necropsy.
GLP compliance:
Test type:
fixed concentration procedure
Limit test:

Test material

Constituent 1
Chemical structure
Reference substance name:
Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate
EC Number:
EC Name:
Silicate(2-), hexafluoro-, disodium, reaction products with lithium magnesium sodium silicate
Cas Number:
Molecular formula:
Synthetic fluorohectorite
Details on test material:
The test material used for this inhalation study was Laponite B, supplied Dec 1982

Test animals


Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body
Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
240 min
Durin the exposure, 5 samples were taken and the dust level ranged between 1.45 0 1.84 g/cubic meter. The average value was determined to be 1.66g/m3. This was the highest practical concentration that could be achieved with the apparatus used for the test. the PSD analysis showed that~47% of the dust was 5.5 microns or less and therefore in the respirable size region
No. of animals per sex per dose:
Exposed to the dust - 5 males, 5 females
Exposed to clean air (control) - 5 males, 5 females
Control animals:

Results and discussion

Effect levels
Dose descriptor:
Effect level:
> 1 660 mg/m³ air
Based on:
test mat.
Exp. duration:
4 h
No deaths were recorded following exposure of 10 rats to Laponite B dust at 1.66g/m3, which was the highest practical level attainable.
Clinical signs:
other: During the exposure: licking of the inside of the mouth, partial closure of eyes, abnormal breathing, lacrimation and lethargy in some animals. Signs were consistent with exposure to a mildly irritant dust. During the observation period: abnormal breathi
Body weight:
For the rats exposed to the dust there was a slight reduction in rate of group mean bodyweight on the day following exposure but after that, the rate of weight gain was similar to the control group.
Gross pathology:
The lung weight to bodyweight ratio were considered to be within normal limits.

Applicant's summary and conclusion

Interpretation of results:
practically nontoxic
Migrated information Criteria used for interpretation of results: expert judgment
This test substance is not toxic to rats by inhalation under conditions of this test
Executive summary:

The level of dust in the air as supplied by the methodology of the test could not be produced at a higher concentration than 1.66mg/l, this was the highest attainable level. At this level, there was no mortality or signs of toxicity exhibited by the exposed rats. As it was not possible to produce sufficiently high concentrations in the atmosphere to cause adverse effects, classification is not considered necessary.  The maximum achieved concentration of 1.66 mg/l is used as part of the derivation of no effect levels