Strategy For Limiting Risks Human Health Draft of ... - ECHA - Europa

0 Summary
Trisodium hexafluoroaluminate (Cryolite) is produced at four sites in the EU-15. In 2006 the
production volume of these four sites was 23,561 t/a of which 11,500 t/a were exported. The
volume for the European market was thus 12,061 t/a. Production capacity was provided by
three companies and it makes 43,200 t/a.
Synthetic cryolite can be obtained by reaction of hydrofluoric acid with aluminium hydroxide
to form fluoroaluminium acid. After treating H3AlF6 with NaCl cryolite precipitates. In
addition, H2SiF6 can be used as starting material in a similar reaction where the precipitated
silicic acid is separated from the reaction solution.
Cryolite is the main constituent of the electrolytic bath in the production of aluminium.
During the electrolytic process cryolite is also formed as a by-product. EAA has provided an
estimate of 24,000 t/a cryolite in the excess bath material produced at the European
aluminium smelter sites.
The main volume of intentionally produced cryolite is used as bath material in aluminium
smelters. Cryolite is also used as filler in synthetic resins for abrasives and as binding agent
for cutting or grinding discs. Minor uses are the use as opacifier in glass and enamel industry,
in pyrotechnics and in ceramic industry.
The classification of trisodium hexafluoroaluminate (cryolite) according to Annex I of
Directive 67/548/EEC (24 th ATP (98/73/EC), Index number: 009-016-00-2):
T; R48/23/25 – Xn; R20/22 – N; R51-53.
The following proposal for a harmonised classification and labelling was laid down in an
Annex XV –Dossier:
Proposed classification based on Directive 67/548/EEC:
T; R48/23/25 – Xn; R20 – Xi; R36 - Repr.Cat.3; R63.
Workers
It has been concluded from the risk assessment that there is a need for limiting the risks due to
repeated dose toxicity (local and systemic effects), and developmental toxicity. On the
background of local effects in the airways air concentrations of cryolite dust at the workplace
should be controlled to a level in the range of 0.1 mg/m 3 (critical exposure level for local
effects after repeated exposure). In doing so also inhalation risks from other endpoints,
especially systemic effects by fluorosis as result of repeated exposure and developmental
toxicity are similarly and effectively mitigated.
Special attention should be given to skin contact. The most critical effect again is repeated
doses systemic toxicity (fluorosis). The critical exposure level is 92 mg/person/day (1.3
mg/kg/day). In the assessment it was assumend that 10% of cryolite is absorbed through the
skin. Considerable (but still practical) effort has to be taken within the framework of
workeplace legislation, in order to achieve the proposed level of dermal exposure. Dermal
risk estimation might be refined by an additional suitable dermal absorption study.
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