tert-butyl isocyanate

Acute Toxicity: inhalation

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: Test procedure in accordance with national standard methods

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:

Seven groups of 5 male and 5 female rats were exposed nose/head only to vapours of 0, 0.7, 5.4, 15.2, 11.7, 27.9, 47.1 or 87.8 mg/m³ (analytical) tert-butylisocyanat for 4 hours. The animals were observed for mortality, body weight and clinical signs through week 4. A gross pathological examination was performed on animals which died intercurrent or were killed after termination of the study.

GLP compliance:

yes

Test type:

standard acute method

Test material

Test material information

Constituent 1

Reference substance name:

109-86-5

IUPAC Name:

109-86-5

Constituent 2

Reference substance name:

tert-butyl isocyanate

EC Number:

216-544-9

EC Name:

tert-butyl isocyanate

Cas Number:

1609-86-5

Molecular formula:

C5H9NO

IUPAC Name:

2-isocyanato-2-methylpropane

Details on test material:

content: 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

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

nominal: 0, 454, 1004, 1486, 1836, 2028, 3597 mg/m³
analytical: 0, 295.9, 777.9, 1071.8, 1144.3, 1391.5, 2510.3 mg/m³

No. of animals per sex per dose:

5 male and female rats/dose

Control animals:

yes

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

ca. 1 593 mg/m³ air

Exp. duration:

4 h

Any other information on results incl. tables

A concentration of 296 mg/m³ tert-butylisocyanate/ m³air ( 4 hr exposure) was tolerated without any clinical symptoms. Body weight was temporily influenced at a concentration of 778 mg/m³. A concentration of 1144 mg/m³ was the threshold of the mortality range.

Vapour of tert-butyl isocyanate is irritating to the respiratory tract.  Animals which died during the post-observation period showed inflated lungs. Liver, spleen and kidneys were pale. A bloddy mucous content was found in the inestinal tract. Mucosa of the intestines were reddened. A lung edema and hydrothorax was evident. Rats which were killed after the post-observation period had no visible macroscopic lung changes.

Applicant's summary and conclusion

Interpretation of results:

toxic

Remarks:

Migrated information

Executive summary:

Seven groups of 5 male and 5 female rats were exposed nose/head only to vapours of 0, 0.7, 5.4, 15.2, 11.7, 27.9, 47.1 or 87.8 mg/m³ (analytical) phenylisocyanat for 4 hours. The animals were observed for mortality, body weight and clinical signs through week 4. A gross pathological examination was performed on animals which died intercurrent or were killed after termination of the study.

A concentration of 296 mg/m³ tert-butyl isocyanate/ m³air ( 4 hr exposure) was tolerated without any clinical symptoms. Body weight was temporily influenced at a concentration of 778 mg/m³. A concentration of 1144 mg/kg was the threshold of the mortality range.

Vapour of tert-butyl isocyanate is irritating to the respiratory tract.  LC50 = 1695 mg/m³ tert-butyl isocyanate/m³ air (rat, male + female). The NOEL was 296 mg/m³ tert-butyl isocyanate/m³ air.