Naphtha (Fischer-Tropsch), light, C4-10-branched and linear

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:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

(see "Principles of method if other than guideline")

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Naphtha (petroleum), light alkylate

EC Number:

265-068-8

EC Name:

Naphtha (petroleum), light alkylate

Cas Number:

64741-66-8

IUPAC Name:

Naphtha (petroleum), light alkylate

Details on test material:

- Name of test material (as cited in study report): Naphtha (petroleum), light alkylate [CAS 64741-66-8]
- Test substance is closely related to Naphtha (Fischer-Tropsch), light, C4-10 - branched and linear; it is defined as : 'A complex combination of hydrocarbons produced by the distillation of the reaction products of isobutane with monoolefinic hydrocarbons usually ranging in carbon numbers from C3 through C5. It consists of predominantly branched chain saturated hydrocarbons having carbon numbers predominantly in the range of C7-C10 and boiling in the range 90-160°C (194-320°F).'

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: males: 278,4 - 310,1g; females: 214,2 - 229,1g
- Fasting period before study: no
- Housing: individually in hanging stainless steel wire mesh cages
- Diet (e.g. ad libitum): Purina Certified Laboratory Chow 5002®, ad libitum
- Water (e.g. ad libitum): Tap, ad libitum
- Acclimation period: yes

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 71-74
- Humidity (%): 44-56
- Photoperiod (hrs dark / hrs light): 12 hour light/dark cycle, artificial light

IN-LIFE DATES:
- Males: from 23 April, 1986 to 26 June, 1986 (date of exposure)
- Females: from 20 April, 1986 to 26 June, 1986 (date of exposure)

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: none

Details on inhalation exposure:

Chamber Operations and Test Substance Administration:
Exposure of the test animals was conducted in a 250 liter stainless steel and glass chamber. The chamber is constructed with a square cross-sectioned area and pyramidal top and base. It was operated in a dynamic mode, with total airflow through the chamber of 2.2 cubic feet per minute (cfm) as measured by a calibrated orifice gauge.
Test material was used as received and was generated as a vapor in the breathing zone of the animals. NAPHTHA (PETROLEUM), LIGHT ALKYLATE was introduced at a rate of 0.34 to 0.51 ml/minute into the top of a vertical counter current heated column. The column was packed with Propac steel mesh and heated by circulation of water from a heated waterbath (74 to 75°C) around the steel mesh. Prewarmed nitrogen gas was introduced at the bottom of the column at a rate of 5.5 to 6.0 liters per minute (1pm). The nitrogen and the NAPHTHA (PETROLEUM), LIGHT ALKYLATE vapours were then mixed with diluting air and introduced into the exposure chamber. Following four hours of exposure, the test material generation system was turned off. Subsequently, air was drawn through the exposure chamber for an additional half-hour period to clear the NAPHTHA (PETROLEUM), LIGHT ALKYLATE vapours. Afterwards, the chamber was opened and the animals were removed.

Atmospheric Sampling:
The exposure chamber atmosphere was recirculated (undiluted) through a Miran 980 infrared (IR) analyzer. Commencing at five minutes after the start of test material generation and at intervals of five to fifteen minutes thereafter, the test atmosphere was analyzed by its IR absorption at 3.393 microns. The atmospheric concentration of NAPHTHA (PETROLEUM), LIGHT ALKYLATE was determined by comparison of absorbance with a standard curve which was prepared with known concentrations of NAPHTHA (PETROLEUM), LIGHT ALKYLATE.
Chamber temperature and relative humidity were monitored continuously during the exposure. Readings were recorded at one-hour intervals. During each hour of the exposure, the test atmosphere was also analyzed gravimetrically and visually (by flashlight) for the presence of any NAPHTHA (PETROLEUM), LIGHT ALKYLATE aerosol. Gravimetric measurement of the test material aerosol concentration was accomplished by drawing a calibrated volume of test atmosphere through a preweighed 25 mm Gelman glass fiber (Type A/E) filter. The aerosol concentration, if any, in the drawn volume was determined by dividing the difference in filter weight by the sample volume.
Appropriate components of the generation system and test material container were weighed before and after the exposure to determine the quantity of test material consumed. This quantity, when divided by the total airflow through the chamber, yielded the nominal exposure concentration.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

analytical: 5040 mg/m³

No. of animals per sex per dose:

5 male and 5 female/dose

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations every 15 minutes during the first hour of exposure, hourly thereafter until completion of exposure. Post-Exposure (Test Days 2-15): for mortality twice daily; detailed physical examination daily. Weighing: One pretest and on Test Days 8 and 15 (Post-exposure days 7 and 14).
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, histopathology

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5 040 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No deaths resulted.

Clinical signs:

other: Clinical signs were languid behaviour and hunched appearance.

Body weight:

No treatment-related effects.

Gross pathology:

No treatment-related effects.

Other findings:

Histopathology (lungs only): histopathology evaluation of the lung were considered unremarkable in that no treatment related effects were apparent.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the conditions of this study, the LC50 for acute inhalation exposure to 'Naphtha (petroleum), light alkylate' is > 5040 mg/m³.

Executive summary:

'Naphtha (petroleum), light alkylate' was administered via individual inhalation chambers for four hours to ten Sprague-Dawley rats at the analytical vapour concentration of 5040 mg/m³ to assess acute inhalation toxicity. Animals were observed for fourteen days following exposure. There were no mortality and the clinical signs observed were languid behaviour and hunched appearance. There were no treatment-related effects observed at necropsy.

Based on the conditions of this study, the LC50 for acute inhalation exposure to 'Naphtha (petroleum), light alkylate' is > 5040 mg/m³.