1-chloro-1,1-difluoroethane

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other: Non-GLP near-guideline study, available as unpublished report, no restrictions, fully adequate for assessment (SIDS score: 1d)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Principles of method if other than guideline:

Experimental assessment of the acute inhalation toxicity of the test substance by administering it to rats at two concentrations for 6 hours.

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1-chloro-1,1-difluoroethane

EC Number:

200-891-8

EC Name:

1-chloro-1,1-difluoroethane

Cas Number:

75-68-3

Molecular formula:

C2H3ClF2

IUPAC Name:

1-chloro-1,1-difluoroethane

Details on test material:

- Test substance name: 1-chloro 1,1-difluoroethane
- The test material was « Aerosol Grade Isotron 142b » from Penwalt Corporation, presented as compressed form in a gas cylinder.
- Purity >99.5%
- Batch number: LBI 1876
- Date of receipt: October 11, 1977

Test animals

Species:

rat

Strain:

other: Charles River CD [CRL:COBS CD (SD) BR]

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Portage, Michigan
- Age at study initiation: adult
- Housing: individually in hanging wire cages in temperature-controlled quaters
- Diet: Purina Laboratory Chow, ad libitum
- Water: ad libitum
- Acclimation period: 8 or 9 days


ENVIRONMENTAL CONDITIONS
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

Dynamic exposure in a 27 liter glass exposure chamber. The test atmospheres were generated by metering the test gas using a rotameter supplied by Pennwalt into an empty exposure chamber set in series with the actual exposure chamber. Volume administred or concentration: 20% and 40% (v/v) in air (820 mg/l and 1640 mg/l respectively).

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

6 h

Concentrations:

200,000 and 400,000 ppm (respectively 20% and 40% in air volume/volume or 820 mg/l and 1640 mg/l)

No. of animals per sex per dose:

5/sex/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: daily
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, histopathology lung and liver

Statistics:

Not applicable

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 400 000 ppm

Exp. duration:

6 h

Remarks on result:

other: LC50 > 1640 mg/l

Mortality:

In the 200,000 ppm exposure group there were no mortalities. In the 400,000 ppm group, there was one death among males and one among females. One animal died after 5 h of exposure and another after 5.5 hours.

Clinical signs:

other: No clinical signs were observed in the 200,000 ppm group. In the 400,000 ppm group all animals showed rapid, laboured breathing and appeared lethargic. A clear discharge from eyes and nose was observed. When administration of the substance was discontinue

Gross pathology:

The 200,000 ppm group animals had normal appearing tissues, with the exception of one male and two female rats which had dark red mottling in all lobes of the lungs. In the 400,000 ppm group the male and female dead rat had dark red lungs and pale livers, the male had a pale spleen; all  surviving rats had dark red mottled lungs; 3 rats had  mottled kidney and one had red spots in its thymus.

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The LC50/6h in acute inhalation study with rats was established to exceed 400,000 ppm.

Executive summary:

Exposure of rats for 6 hours to a test atmosphere of 200,000 ppm of 1-choro 1,1-difuoroethane produced no gross signs of toxicity or death. Three animals on necropsy showed signs of lung damage. Exposure of rats for 6 hours to a test atmosphere of 400,000 ppm of 1-chloro 1,1-difluoroethane

produced lethargy, labored respiration and death in 20% of the exposed population. All animals on necropsy showed signs of lung damage. The LC50/6h was >400,000 ppm. Based on this key study, 1-chloro-1,1-difluoroethane is of low acute toxicity.