Hydrocarbons, C10, aromatics, >1% naphthalene

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November, 15, 1994 to December 1, 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented study report in general agreement with OECD guideline 403-GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

only one dose tested

GLP compliance:

yes

Test type:

standard acute method

Test material

Test material information

Constituent 1

Reference substance name:

Hydrocarbons, C10, aromatics, >1% naphthalene

EC Number:

919-284-0

Cas Number:

Not applicable

Molecular formula:

None available - not a single isomer - see remarks

IUPAC Name:

Hydrocarbons, C10, aromatics, >1% naphthalene

Details on test material:

- Name of test material (as cited in study report): MRD-94-953
- Physical state: Colorless liquid
- Stability under test conditions: : Not documented. Material stable under normal conditions
- Storage condition of test material: Room temperature

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Inc.
- Age at study initiation: approximately 8-10 weeks
- Weight at study initiation: 225-296 grams
- Housing: individually
- Diet (e.g. ad libitum): ad libitum during non-exposure periods. Food withheld while animals were in chamber
- Water (e.g. ad libitum): ad libitum during non-exposure periods. Food withheld while animals were in chamber
- Acclimation period: eight days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): maintained range 20-24.4
- Humidity (%): maintained range of 40-70
- Photoperiod (hrs dark / hrs light): 12hrs dark / 12hrs light


IN-LIFE DATES: From: November 17, 1994 To: December 1, 1994

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 150 liter stainless steel inhalation chamber
- Exposure chamber volume: 150 liter
- Method of holding animals in test chamber:
- Source and rate of air: chamber operated under slight negative pressure to the room at an airflow of approximately 30.0 liters per minute
- Method of conditioning air:
- System of generating vapor: test material was delivered by a syringe pump to the inside of a heated glass counter current vapor generator
- Treatment of exhaust air:
- Temperature, humidity, pressure in air chamber: approximately 23.8 C


TEST ATMOSPHERE
- Brief description of analytical method used: vapor concentrations were determined during exposure by drawing chamber air through a calibrated infrared monitor. chamber concentrations were recorded at approximately 1 hour intervals and averaged to yield the mean chamber concentration for exposure
- Samples taken from breathing zone: yes



CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: highest attainable vapor concentration

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

ca. 4 h

Concentrations:

average actual vapor concentration of 4688 mg/m3 (± 72 mg/m3)

No. of animals per sex per dose:

10 animals (5 males; 5 females)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Animals were observed in chamber during exposure at 15, 30, and 45 minutes and at 1, 2, 3, and 4 hours. Animals were observed once daily for 14 days. Body weights were measured before exposure and on days 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight, organ weights, histopathology, other:

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 4 688 mg/m³ air (analytical)

Remarks on result:

other: no mortality or gross systemic toxicity observed at this dose

Clinical signs:

other: all animals appeared normal during the 14-day post-exposure observation period, except one male with red ocular discharge on day 5 post-exposure

Body weight:

Body weight gain for all animals appeared normal throughout the observation period with the exception of one female whose weight remained unchanged from day 7 to day 14

Gross pathology:

all animals appeared normal at the gross postmortem examination

Applicant's summary and conclusion

Interpretation of results:

other: Not classified

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

The LC50 for acute inhalation exposure to MRD-94-953 vapor is greater than the highest obtainable vapor concentration (4688 mg/m3). Classification as an acute inhalation toxicant is not warranted under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.

Executive summary:

The acute inhalation toxicity of MRD-94-953 was evaluated in ten Sprague-Dawley rats.  Animals were exposed for four hours to the maximum attainable vapor concentration of the test material (4688mg/m3) in individual inhalation chambers. Animals were observed for 14 days.  There were no mortality or gross pathological alterations noted in any of the animals.  Based on the conditions of this study, the LC50for vapors of MRD-94-953 are greater than 4688mg/m3. Classification as an acute inhalation toxicant is not warranted under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP) or under Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations.