p-tolyl isocyanate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

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)

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

Test material information

Constituent 1

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 levels

Effect levels 1

Sex:

male

Dose descriptor:

LC50

Effect level:

33 mg/m³ air

Based on:

test mat.

95% CL:

26 - 44

Exp. duration:

4 h

Effect levels 2

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.