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Acute Toxicity: inhalation

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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:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Non GLP, non-guideline, animal experimental study. Limitations in design and reporting but otherwise adequate for assessment

Data source

Reference
Reference Type:
publication
Title:
Hydrocarbon mixture: propane, butane and isobutane
Author:
Aviado DM, Zakheri S and Watanabe T
Year:
1977
Bibliographic source:
Non-Fluorinated Propellants and Solvents for Aerosols, pp 75-81

Materials and methods

Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
To determine whether a mixture of 3 hydrocarbons is more toxic than each individual component.
Groups of male mice were exposed to a mixture of isobutane, butane, and propane (80.4%, 2.5%, and 17.1%, respectively) in air for 2 hours. Oxygen was added to prevent death from hypoxia.
GLP compliance:
no
Test type:
other: LC50
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Isobutane
EC Number:
200-857-2
EC Name:
Isobutane
Cas Number:
75-28-5
Molecular formula:
C4H10
IUPAC Name:
isobutane
Constituent 2
Chemical structure
Reference substance name:
Propane
EC Number:
200-827-9
EC Name:
Propane
Cas Number:
74-98-6
Molecular formula:
C3H8
IUPAC Name:
propane
Constituent 3
Chemical structure
Reference substance name:
Butane
EC Number:
203-448-7
EC Name:
Butane
Cas Number:
106-97-8
Molecular formula:
C4H10
IUPAC Name:
butane
Test material form:
gas
Details on test material:
- Name of test material (as cited in study report): A-46
- Substance type: A hydrocarbon mixture specifically developed for the purpose of substituting for fluorocarbons
- Physical state: gas
- Composition of test material, named A-46, percentage of components: isobutane (31 psig) 80.4%, butane (17 psig) 2.5% and propane (108 psig) 17.1%
- Mixture A-26 (46 psig at21.1° ) 100%
Specific details on test material used for the study:
- Name of test material (as cited in study report): A-46
- Substance type: A hydrocarbon mixture specifically developed for the purpose of substituting for fluorocarbons
- Physical state: gas
- Composition of test material, named A-46, percentage of components: isobutane (31 psig) 80.4%, butane (17 psig) 2.5% and propane (108 psig) 17.1%
- Mixture A-26 (46 psig at 21.1°C) 100%

Test animals

Species:
mouse
Strain:
CF-1
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Wilmington, Massachusetts, USA
- no further details

ENVIRONMENTAL CONDITIONS
- no data

IN-LIFE DATES
- no data

Administration / exposure

Route of administration:
inhalation: gas
Type of inhalation exposure:
whole body
Vehicle:
other: no data
Details on inhalation exposure:
No methods in the paper itself, the publication refers to an earlier chapter (see other Aviado 1977 reference):
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Glass chamber
- Exposure chamber volume: 10 L
- Source and rate of air:The gaseous mixture was flushed into the chamber at a rate of 3 L/min

All gaseous mixtures were balanced by adding oxygen (25% of the volume of A-46).
Analytical verification of test atmosphere concentrations:
not specified
Duration of exposure:
120 min
Concentrations:
45, 50, 55, 60, 70 and 75 % v/v
No. of animals per sex per dose:
10 males
Control animals:
no
Details on study design:
Duration of observation period following administration: none
Statistics:
An LC50 and 95% confidence limits were calculated by a probit method

Results and discussion

Effect levelsopen allclose all
Sex:
male
Dose descriptor:
LC50
Effect level:
57.42 other: %
95% CL:
>= 53.96 - <= 60.88
Exp. duration:
120 min
Remarks on result:
other: mixture material. Regression coefficient 0.9811
Key result
Sex:
male
Dose descriptor:
LC50
Effect level:
539 600 ppm
Exp. duration:
120 min
Mortality:
Mortality was 0, 20, 50, 60, 80 and 100% at concentrations of 45, 50, 55, 60, 70 and 75%, respectively.
Clinical signs:
other: None reported
Body weight:
None reported
Gross pathology:
n/a
Other findings:
n/a

Any other information on results incl. tables

n/a

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Remarks:
Criteria used for interpretation of results: other: EU (GHS/CLP)
Conclusions:
The 2-hour LC50 in mice of a mixture of isobutane, butane, and propane (80.4%, 2.5%, and 17.1%, respectively) was 57.42% (approximately 539,600 ppm).
Executive summary:

In this study, groups of male mice were exposed to a mixture of isobutane, butane, and propane (80.4%, 2.5%, and 17.1%, respectively) in air for 2 hours to assess the lethality and whether a mixture of 3 hydrocarbons is more toxic than each individual component.

The LC50 of the gas mixture was 57.42% (approximately 539,600 ppm). Mortality was 100% at a concentration of 75%.