Registration Dossier

Toxicological information

Repeated dose toxicity: inhalation

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Administrative data

Endpoint:
repeated dose toxicity: inhalation
Remarks:
combined repeated dose and carcinogenicity
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
review article or handbook
Title:
Recommendation from the Scientific Committee on Occupational Exposure Limits for Calcium oxide (CaO) and calcium hydroxide (Ca(OH)2)
Author:
Scientific Committee on Occupational Exposure Limits
Year:
2008
Bibliographic source:
SCOEL/SUM/137, February 2008

Materials and methods

Test guideline
Qualifier:
no guideline available
Guideline:
other: Repeated studies in human
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent

Test animals

Species:
other: Human

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
whole body

Results and discussion

Effect levels

Dose descriptor:
NOAEL
Effect level:
ca. 1 mg/m³ air
Based on:
test mat.

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The Scientific Committee on Occupational Exposure Limits defined an 8 hour TWA (Time Weighted Average) for Calcium hydroxide of 1 mg/m3 with a STEL (Short Term Exposure Limit) of 4 mg/m3 for 15 minutes.
This leads to an OEL for CAHC of 2.5 mg/m³ with a STEL of 10 mg/m³
Executive summary:

The effects of Calcium hydroxide are considered to be limited to the external surface of the body and no systemic effects are foreseen.Assuming an exposure level of 1 mg/m3and an inhalation of 10 m3of air during an 8-hour workday, this would result in an inhaled dose of 5.4 mg calcium per day. Overall, the occupational exposure would only increase the body burden of calcium to a negligible extent as the Tolerable Upper Intake Level is 2,500 mg of calcium per day.

At low-level exposures, sensory irritation and a decrease of the lung function parameters at long-term exposures are considered to be the critical effects.From a well conducted acute human study with Calcium oxide, sensory irritation is expected to be avoided at 1 mg/m3of respirable dust. No relevant respiratory effects were seen at an exposure level of 1 mg/m3of total dust among kiln workers producing. One mg of Calcium hydroxide per m3 is therefore obviously protective against adverse effects from long-term exposure to Calcium hydroxide and this concentration is supported by data from exposure to cement dust that has a similar alkalinity.

The Scientific Committee on Occupational Exposure Limits defined an 8 hour TWA (Time Weighted Average) for Calcium hydroxide of 1 mg/m3 with a STEL (Short Term Exposure Limit) of 4 mg/m3 for 15 minutes.

This leeds to an OEL for CAHC of 2.5 mg/m³ with a STEL of 10 mg/m³