tert-butyl methyl ether

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, non-guideline study, some restrictions in reporting, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1969

Report date:

1969

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

tert-butyl methyl ether

EC Number:

216-653-1

EC Name:

tert-butyl methyl ether

Cas Number:

1634-04-4

Molecular formula:

C5H12O

IUPAC Name:

2-methoxy-2-methylpropane

Details on test material:

MTBE, X-801-25, 100%

Test animals

Species:

rat

Strain:

other: Charles River albino

Sex:

male/female

Details on test animals or test system and environmental conditions:

The animals had a average body weight of 240 grams.
The animals were housed individually.
The animals were permitted a standard laboratory diet plus water ad libitum.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23-25
- Test atmosphere pressure (inches Hg): 29.90-30.24

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

not specified

Details on inhalation exposure:

Exposure was in a Plexiglas inhalation chamber of 70 liters. The chamber was designed so that the animals could be introduced to the test atmosphere after 99 percent of the desired vapour concentration was established.
Vapour was generated by bubbling a stream of clean dry air through the undiluted test material. The resulting air-vapour stream was then introduced into the exposure chamber at the top center, dispersed by a baffle plate and exhausted at the bottom of the chamber.
Average nominal vapour generation were calculated by dividing the total weight of test material vaporized by the total volume of air used during each inhalation exposure.

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

4 h

Concentrations:

44, 65, 86, 99, 167 and 395 mg/l

No. of animals per sex per dose:

5/sex/dose

Control animals:

not specified

Details on study design:

Each experiment was designed to run for a four-hour period during which time observations were made with respect to incidence of mortality and reactions displayed. At the end of the exposure period, the rats were returned to their stock cages and observed for the following 14 days.
A body weight was determined for each animal at the end of the 14-day observation period. Gross pathologic examinations were scheduled to be conducted upon all animals which might succumb during the test period as well as those sacrificed at the end of the 14 day observation period.

Statistics:

The LC50 was calculated using the techniques of Litchfield and Wilcoxon.
For analysis of the effects, no details were reported.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

85 mg/L air

95% CL:

> 79 - < 91

Exp. duration:

4 h

Mortality:

In the 86 mg/l group, six animals died and in the higher dose groups, all animals died. In the 86 mg/l concentration group, the time of death varied from 110 to 225 minutes after the start of exposure, in the 99 mg/l concentration group, the time of death varied from 96-240 minutes, in the 167 mg/l concentration group, the time of death varied from 59-80 minutes and in the high dose group, the time was 25-51 minutes.

Clinical signs:

other: The clinical signs included ataxia, tremors, lacrimation, clonia, unconsciousness and hyperactivity. Surviving animals appeared normal the morning after exposure.

Body weight:

No adverse effects were observed.

Gross pathology:

Necropsy of the animals which died revealed slight to moderate hyperemia in the lungs. The animals that survived the 14-day observation period had minimal to mild lung hyperemia.