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Toxicological information

Acute Toxicity: inhalation

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Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: guideline study - well documented

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report date:
1988

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Principles of method if other than guideline:
Thirteen groups of 5 to 10 male and female rats each were exposed nose/head-only to 0, 25, 62, 74, 99, 111, 159, 169, 173, 176, 274, 331, or 492 mg/m³ m-tolylisocyanate (vapour) for 4 hours.
GLP compliance:
yes
Test type:
standard acute method

Test material

Constituent 1
Chemical structure
Reference substance name:
m-tolyl isocyanate
EC Number:
210-676-0
EC Name:
m-tolyl isocyanate
Cas Number:
621-29-4
Molecular formula:
C8H7NO
IUPAC Name:
1-isocyanato-3-methylbenzene
Details on test material:
m-tolylisocyanate: purity: 99.7 %

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure:
nose/head only
Vehicle:
air
Duration of exposure:
4 h
Concentrations:
0, 25, 62, 74, 99, 111, 159, 169, 173, 176, 274, 331, or 492 mg/m³
No. of animals per sex per dose:
5 to 10 male and 5 to 10 female rats/dose
Control animals:
yes

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LC50
Effect level:
33 mg/m³ air
Based on:
test mat.
95% CL:
26 - 44
Exp. duration:
4 h
Sex:
female
Dose descriptor:
LC50
Effect level:
30 mg/m³ air
Based on:
test mat.
95% CL:
24 - 39
Exp. duration:
4 h

Any other information on results incl. tables

A concentration of 6.6 mg/m³ m-tolylisocyanate for 4 hours was tolerated by the rats without clinical symptoms. A concentration of 13 mg/m³ influenced the body weight and was the beginning of the mortality range.

m-tolylisocyanate has a strong irritation potential on the respiratory tract. The duration of the symptoms are determined by the breathing discomfort, which have a low tendency to reversibility. In the lower concentration range the breathing discomfort was evident after 1 week. Therefore rats died during the post-exposure period which had no symtoms immediately after the exposition to m-tolylisocyanate.

Applicant's summary and conclusion

Interpretation of results:
very toxic
Remarks:
Migrated information
Executive summary:

Thirteen groups of 5 to 10 male and female rats each were exposed nose/head-only to 0, 25, 62, 74, 99, 111, 159, 169, 173, 176, 274, 331, or 492 mg/m³ m-tolylisocyanate (vapour) for 4 hours.

A concentration of 6.6 mg/m³ m-tolylisocyanate for 4 hours was tolerated by the rats without clinical symptoms. A concentration of 13 mg/m³ influenced the body weight and was the beginning of the mortality range.

m-tolylisocyanate has a strong irritation potential on the respiratory tract. The duration of the symptoms are determined by the breathing discomfort, which have a low tendency to reversibility. In the lower concentration range the breathing discomfort was evident after 1 week. Therefore rats died during the post-exposure period which had no symtoms immediately after the exposition to m-tolylisocyanate.

The NOEL for male and female rats is 6.6 mg/m³ m-tolylisocyanate in air.