Hexabromocyclododecane

Endpoint summary

Description of key information

The key study for each route of exposure was chosen for this endpoint as follows:
Oral exposure route:
Dean, W. P. and Leong, B. K. J. (1977a). Acute toxicity study in Rabbits and Rats.Report no.: 163-499. Report date: 1977-12-07.
Dermal exposure route:
Dean, W. P. and Leong, B. K. J. (1977a). Acute toxicity study in Rabbits and Rats. Report no.: 163-499.Report date: 1977-12-07.
Inhalation route:
Dean, W. P. and Leong, B. K. J. (1977a). Acute toxicity study in Rabbits and Rats. Report no.: 163-499. Report date: 1977-12-07.
Dean and Long (1977a)  was chosen as the key study for each route of exposure based upon the result of the reliability assessment, age of the study and depth of reporting. This study was awarded a reliability score of 2 according to the Klimisch et al. (1997) criteria. Although other sources of available information were also awarded a reliability score of 2 according to the same criteria, it was considered that this study provided more complete reporting of test methodology and results and so was chosen as the key study.

Additional information

Key information for chemical safety assessment:

Acute toxicity: oral

Descriminating dose >10,000 mg/kg bw (male/female)

Acute toxicity: dermal

Descriminating dose >20,000 mg/kg bw (male/female)

Acute toxicity: inhalation

Descriminating concentration (4 hours) >202.14 mg/l air (nominal)

Discussion

Dean and Long (1977) was selected as the key study for each exposure route as stated above. The results of the key studies were supported by other additional non-key studies as follows:

Acute toxicity: oral

All available information reported a lack of mortality and systemic toxicity for the oral route. A short summary of results is provided below:

Reference	Result
Nissimov (1984)	LD50: >5000 mg/kg bw (male/female)
Lewis and Palanker (1978a)	LD50: >10 g/kg (male/female)
Ogaswara et al. (1983)	LD50: >20000 mg/kg bw (male)
Tobe et al. (1984)	LD50: >20 g/kg (male/female)
Ishizu et al.	LD50: >40 g/kg (male/female)

Acute toxicity: dermal

Lewis and Palanker (1978) supported the key study and found no mortality or signs of systemic toxicity after exposure to the substance by the dermal route. Lewis and Palanker reported an LD50 of >8 g/kg (male/female) based upon an absence of mortality at the highest dose level tested. The key study (Dean and Long, 1977) confirms this result with the reported LD50 of >20,000 mg/kg bw (male/female).

Acute toxicity: inhalation

As for dermal toxicity Lewis and Palanker (1978) is provided in support of the key study. Lewis and Palanker (1978) reported an LC50 value of >200 mg/l air (nominal) (male/female). This value supported the key study (Dean and Long, 1977) which reported a result of 202.14 mg/l air (nominal) (male/female).

Justification for classification or non-classification

Multiple studies have demonstrated that HBCDD is not acutely toxic by the oral, dermal and inhalation routes. Thus HBCDD does not meet the criteria for classification as acutely toxic according to Directive 67/548/EEC and EC Regulation 1272/2008.