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Administrative data

acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with GLP and OECD guideline, available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
OECD Guideline 403 (Acute Inhalation Toxicity)
GLP compliance:
yes (incl. certificate)
TNO Utrechtseweg 48, 3700 AJ Zeist, The Netherlands
Test type:
standard acute method
Limit test:

Test material

Test material form:
gas under pressure: liquefied gas
Details on test material:

- Storage conditions : ambient temperature (15-25ºC)

Test animals

Details on test animals and environmental conditions:
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: Approx: 9-10 weeks
- Weight at study initiation: Pilot 1: 394.9g (male) 224g (female); Pilot 2: 392.8g (male) 221.3g (female); Group A: 420.4g (male) 249.5g (female); Group B: 405.7g (male) 250.8g (female); Group C: 358.7g (male) 261g (female)
- Housing: macrolon cages bedding of wood shavings (Lignocel, type 3/4, Rettenmaier, Rosenberg, Germany) and strips of paper (Enviro-dri, Lillico, Betchworth, England), pilot studies: individualy, main study: 5 males or 5 females per cage
- Diet: ad libitum commercially available rodent diet (Rat & Mouse No. 3 Breeding Diet RM3) from SDS Special Diets Services, Witham, England except withheld during exposure
- Water: ad libitum except withheld during exposure
- Acclimation period: Pilot 1: 19 days; Pilot 2: 20 days; Group A: 25 days; Group B: 27 days; Group C: 7 days

- Temperature (°C): 20 - 24
- Humidity (%): 40 -70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: gas
Type of inhalation exposure:
nose only
Details on inhalation exposure:
- Exposure apparatus: cylindrical stainless steel column, surrounded by a transparent cylinder.
- Exposure chamber volume: ca. 50 litres
- Method of holding animals in test chamber: plastic animal holders (Battelle)
- Source and rate of air: humidifed compressed air, in addition oxygen added to ensure oxygen concentration of at least 19.5%
- Temperature, humidity, pressure in air chamber: 21.3 – 23.9°C; 37.2 -62.9% humidity; 20.5 - 20.9% oxygen

- Brief description of analytical method used: total carbon analyzer
- Samples taken from breathing zone: yes
Analytical verification of test atmosphere concentrations:
Duration of exposure:
ca. 4 h
Pilot 1: 200000 ppm
Pilot 2: 50000 ppm
Main test: 96000, 156000, 120000ppm
No. of animals per sex per dose:
Pilot 1: 1
Pilot 2: 1
Main study: 5
Control animals:
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: body weights on day 0, 7 and 14; clinical signs daily
- Necropsy of survivors performed: yes
The 4-h LC50 was calculated using according to Finney (Finney D.J., Probit Analysis, Cambridge University Press, 1997) using a computer program (Wil ten Berge, 2006, Dose Respons Beta 2006 WtB.xls).

Results and discussion

Effect levels
Dose descriptor:
Effect level:
120 000 ppm
Based on:
test mat.
95% CL:
>= 108 500 - <= 133 800
Exp. duration:
4 h
Pilot 1: both animals died during exposure
Pilot 2: both animals survived
Main study: one female died during exposure to 96000 pp; 1 female and 3 males in Group C (120000 ppm) died during exposure; all animals in Group B (156000 ppm) died during exposure.
Clinical signs:
other: Pilot 2: shallow breathing at an increased rate (slight) during exposure. Group A: During exposure: clear restlessness and tremors in tail and body (slight) in all rats; haemorrhagic discharge from the mouth in one male. Shortly after exposure: clear rest
Body weight:
Group A: One male animal showed appreciably weight loss on day 1, during the remainder of the 14-day observation period body weight increased again to almost the pre-exposure level. The other animals that survived the exposure demonstrated increases in body weight during the observation period which are within the range for animals of this strain and age.
Group C: Surviving animals demonstrated variability with respect to body weight gain ranging from weight gain as expected in two animals to weight loss during both the first and the second observation week. Weight loss was observed in all animals that died during exposure and were weighed at necropsy
Gross pathology:
Pilot 1: Haemorrhagic discharge from the nose and mouth and a red discolouration of the lungs in both animals
Pilot 2: No abnormalities obseved
Group A: Gray discoloured lungs in one male and four female animals. Two males had petechiae in the lungs. No abnormalities were found in the female that was found dead on day 1.
Group B: Red spots on the thymus of two females, petechiae in the lungs of one male animal and a dark red discolouration of the upper lung lobes in another male rat.
Group C: All animals found dead during exposure (one female, 3 males) showed soiled fur, black discoloured tail, and enlarged and red discoloured (and in two cases haemorrhagic) lungs. No abnormalities were found at necropsy of the surviving animals.

Any other information on results incl. tables

Mean (rounded) test atmosphere concentrations and generation efficiencies:

Pilot 1 (target 200,000 ppm): actual concentration 200,000 ppm (total carbon analysis); generation efficiency 105%

Pilot 2 (target 50,000 ppm): actual concentration 50,000 ppm (total carbon analysis); generation efficiency 98%


Group A (target 100,000 ppm): actual concentration 96,000 ppm (total carbon analysis); generation efficiency 93%

Group B (target 125,000 ppm): actual concentration 156,000 ppm (calculated from rotameter readings; value obtained by total carbon analysis [131,000 ppm] was incorrect, probably due to an unexplained change in the sensitivity of the equipment); generation efficiency 96%

Group C (target 120,000): actual concentration 120,000 (total carbon analysis); generation efficiency 98%

Applicant's summary and conclusion

Interpretation of results:
not classified
Migrated information Criteria used for interpretation of results: EU
The 4-hour LC50 for rats of both sexes combined was calculated to be 120000 ppm (exposure nose only).
Executive summary:
The acute inhalation toxicity of the test substance was determined in a study with Sprague-Dawleys rats performed according to OECD guideline 403 and GLP. To assess a suitable concentration range for the main study, two pilot experiments were carried out in which groups of 1 male and 1 female were exposed to levels of 50000 or 200000 ppm of the test substance for 4-hours. All rats in the 50000 ppm exposure level group survived while all rats in the 200000 ppm exposure level group died. In the main study, groups of 5 male and 5 female rats were exposed to 96000, 120000, or 1560000 ppm, for 4 hrs and held for an observation period of 14 days. One female in the 96000 ppm exposure level group, 3 males and 1 female in the 120000 ppm exposure level group and all animals in the 156000 exposure level group died. Clinical signs included tremors or the tail and body, lethargy, hunched appearance, piloerection, blepharospasm, exophthalmus and restlessness as well as a red brown discoloration of the head (only one male). These signs were seen during exposure, immediately after exposure and during the first few days following exposure. Body weight gain in surviving animals exposed to 96,000 ppm was as expected for animals of this strain and age. For surviving animals exposed to 120,000 ppm, however, weight gain varied between weight loss in both observation weeks and normal weight gain in both observation weeks. The main macroscopic finding in animals that died was red discoloration of the lungs. Except for gray discoloration in some lungs and a few observations of petechiae, no abnormalities were found at necropsy of the animals surviving until the 14 day sacrifice. The LC50 was calculated to be 120000 ppm (95% confidence interval limits: 108500 – 133800 ppm).