Registration Dossier

Administrative data

Description of key information

Toxicity via the oral route is addressed by upper intake levels (UL) for adults determined by the Scientific Committee on Food (SCF), being UL = 2500 mg/d, corresponding to 36 mg/kg bw/d (70 kg person) for calcium. Toxicity of “Reaction mass of Limestone and dicalcium silicate” via the dermal route is not considered as relevant.
Toxicity of the substance via inhalation (local effect, irritation of mucous membranes) is addressed by read-across from an 8-h TWA determined for CaO and Ca(OH)2 by the Scientific Committee on Occupational Exposure Limits (SCOEL) of 1 mg/m³ respirable dust.

Key value for chemical safety assessment

Additional information

Guideline-compliant repeated-dose toxicity studies in rodents with oral administration of the various calcium compounds (28-day study acc. to OECD TG 407 or 90-day study acc. OECD TG 408) are not available. None of the five animal studies available for various calcium salts allow the derivation of a NOAEL or LOAEL value for quantitative risk assessment purposes. However, the Scientific Committee on Food has determined an upper intake level (UL) of calcium for adults of 2500 mg/d, corresponding to 36 mg/kg bw/d, taking into account an average body weight of 70 kg/person. A dermal repeated-dose toxicity study for test substance is considered to be scientifically unjustified. A repeated-dose toxicity study for test susbstance via the inhalation route is considered to be scientifically unjustified. Instead, the adopted Recommendation from the Scientific Committee on Occupational Exposure Limits (SCOEL) for Calcium oxide (CaO) and calcium hydroxide (Ca(OH)2) has determined an 8-h TWA of 1 mg/m³ (respirable dust) which is considered protective against adverse effects in case of long-term exposure to CaO and Ca(OH)2. Effects upon inhalation test substance are purely local, i. e. irritation provoked by a pH shift. This effect is determined by calcium hydroxide as the most alkaline constituent of test substance. The other main constituents and major impurities (calcium carbonate, calcium silicate, calcium silicate and calcium sulphate) are considered as non-relevant in terms of toxicity by inhalation. Calcium hydroxide and target substance cause an equivalent pH shift. Therefore the respective 8-h TWA can be adopted for test substance by read-across.

Justification for classification or non-classification

The only toxicologically relevant effect of the substance is local irritation through a pH shift, which is not relevant for classification for repeated-dose toxicity. Therefore, classification of the substance for toxicity upon prolonged exposure is not required.