Lithium stearate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size

Justification for type of information:

The category members are almost exclusively produced and used directly in grease form. They have vapour pressures of around or below 10 E-10 Pa and melting points of greater than 160°C, so the potential for the generation of inhalable forms is low, also the use of the grease forms will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be unlikely to occur. Only two category substances – Fatty acids C16-18, lithium salts and lithium 12-hydroxystearate – are produced to some extent in solid form and then subsequently formulated by occupational downstream users into a grease form. From the granulometry data on the solid, generation of dusts of an inhalable size cannot be excluded. However, at the production and occupational downstream users sites, the formation of dusts/aerosols is not significant due to specific operational conditions and implemented general dust RMMs. None of the category substances have been tested by the inhalation route. However, a number of acute oral and dermal toxicity studies in rats conducted on lithium salts of myristic (C14),stearic (C18), 12-hydroxystearic (C18 hydroxylated), C18 unsaturated and behenic (C22) monocarboxylic acids showed consistent evidence of a lack of acute toxicity up to the highest doses tested (2000 mg/kg or greater). An estimate of the inhalation LC50 by route-to-route extrapolation using a respiratory volume for a 250 g rat of 0.20 l/min and 100 % absorption and postulating 100% deposition and absorption (c. f. ECHA REACH TGD R.8, Table R.7-2 (ECHA 2012c) and ECHA CLP TGD 3.1.3.3.4i: Extrapolation oral to inhalation (ECHA 2012d)) result in an ATE of in minimum 10.4 mg/L/4h. This value is well above the cut values for classification an acute toxicity hazard of dusts. Although no substance specific intrinsic inhalative toxicity is expected, generally accepted OELs derived for inert (nuisance) dust/particulates not otherwise classified (PNOCs) of 10 mg/m³ for chronic and 20 mg/m³ for acute exposure to inhalable dust and of 3 mg/m³ for chronic and of 6 mg/m³ for acute exposure to alveolar (respirable) dust are applicable and must be adhered to, to avoid non-specific inhalative dust toxicity. By adherence to the general dust limits, the risk to humans can be considered to be sufficiently controlled. In accordance with ECHA REACH TGD R.8, the general dust limits are used as DNEL surrogate. In accordance with REACH Regulation, Annex XI, 1. and 3., an acute toxicity study by inhalation is not justified due to toxicological as well as exposure considerations and consequently no acute inhalation test was performed.