Trisodium hexafluoroaluminate

Endpoint summary

Description of key information

Cryolite is not irritating to the skin, eyes and respiratory tract.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

One primary dermal irritation study is available (Raltech Scientific Services, 1981a). New Zealand White rabbits (3 males and 3 females) were exposed to 0.5 g cryolite (moistened with sterile 0.9% saline) for 24 hours under occlusive conditions (intact and abraded skin). After treatment the patches were removed and the test material was wiped (not washed) from the area as thoroughly as possible without irritation to the skin. The degree of erythema and edema was read according to the Draize technique. A second reading was taken at 72 hours. The primary irritation index and the scores for erythema and edema were zero at both time points for both intact and abraded skin. Cryolite was not irritating to the skin in this study.

As part of the available skin sensitisation study, a preliminary irritation study was conducted (NOTOX, 1998). Four guinea pigs were tested on shaved skin under occlusive conditions (50%, 20%, 10%, 5%; vehicle: aqueous carboxymethyl cellulose; 2 animals/concentration; 2 concentrations/animal). After 24 hours, the dressing was removed and the skin cleaned of residual test substance. The treated skin areas were assessed for irritation 24 and 48 hours after exposure. The scores for erythema and edema were zero at both time points for all tested concentrations.

For eye irritation, a primary eye irritation study was available (Raltech Scientific Services, 1981b). New Zealand White rabbits were divided into two groups: group I with six rabbits and group II with three rabbits. Each animal received 0.1 g of the substance on the everted lower lid of one eye, with the contra-lateral eye serving as the untreated control. The upper and lower lids were gently held together for one second to prevent loss of material and then released, the treated eyes of group II animals were flushed for one minute with lukewarm water, starting 30 seconds after test material administration. The eyes of group I rabbits remained unflushed. The treated eyes of both groups were observed for ocular lesions at 24, 48, 72 and 96 hours and at 7 days after treatment. Irritation was graded and scored according to the Draize technique. The cornea, iris, conjuntivae and chemosis score (mean values over 24, 48 and 72 hours) for group I animals were 0, 0.06, 0.94 and 0.36, respectively. The cornea, iris, conjuntivae and chemosis score (mean values over 24, 48 and 72 hours) for group II animals were 0, 0, 0.94 and 0.22, respectively. Based on both the mean and individual scores, cryolite is not considered irritating to the eyes.

Regarding the respiratory tract, while some local effects were observed, as a whole the results do not meet the requirements for classification as a respiratory tract irritant. After a 4-hour continuous whole-body exposure to synthetic cryolite (Huntingdon Research Centre Ltd., 1993), clinical signs were observed which are indicative of respiratory irritation: partial closing of the eyes was observed after exposure at 4.34 mg/L, exaggerated respiratory movements were noted at 2.83 mg/L and no signs were detected at 1.33 mg/L.

In two 2-week range finding inhalation toxicity studies, also signs indicative for respiratory tract irritation were observed. In the first study the mean exposure levels were 5.1 mg/m³(low dose) or 13.6 mg/m³(high dose). Various inflammatory lesions were detected in alveolar parenchyma, and lymphoid hyperplasia was reported in the tracheobronchial and mediastinal lymph nodes of the treated male and female rats (Huntingdon Research Centre Ltd., 1994a). In the second study, after repeated exposure to 470 mg/m³(6 hours/day), histopathology reported findings indicative for respiratory tract irritation, i.e. inflammatory reactions in the respiratory epithelia (Huntingdon Research Centre Ltd., 1994b).

From human examinations no local effects on the respiratory tract were described.

Justification for classification or non-classification

In accordance to Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008, classification is not necessary for skin, eye and respiratory tract irritation based on the available data.