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Key value for chemical safety assessment

Additional information

No data concerning repeated dose toxicity are available for diethyl ether boron trifluoride. But data are available for the leading toxophore boron trifluoride.

Boron trifluoride (CAS:13319-75-0) was tested in a 13-week inhalation study (Rusch et al., 1986). The substance was tested in a dihydrate form which contained 63.87% of BF3. Aerosols of BF3 dihydrate were offered daily by inhalation to male and female Fischer 344 rats, 6 hrs/day, 5 days a week, at dose levels of 0, 2, 6, 17 mg/m3. At 17 mg/m3, one death was attributed to the test substance. No differences were observed between treated and control groups for body weight and haematology. Urine analysis and blood chemistry were affected by treatment. Clinical signs of respiratory irritation were seen, but without abnormal histological findings. An exposure-related depression of total protein concentrations accompanied by an exposure-related depression of globulin concentrations was observed. In urines, an exposure-related depression in calcium amounts and an exposure-related increase in urinary fluoride were noted. The decrease in calcium values was found to be reversible at the end of exposure, contrary to the decrease of urinary fluoride which was partially reversible. Serum fluoride concentration were markedly increased in all exposure groups (dose-related increase). A recovery was noted after the end of exposure. At necropsy, no differences for organ weight and macroscopic appearance were observed between treated and control groups. At microscopy examination, necrosis of the renal tubular epithelium was seen in the highest dose group and was the apparent cause of a death in one of the animals. Consequently, under the experimental conditions, the NOAEC was found to be 6 mg/m3 and the LOAEC was found to be 17 mg/m3 for effects on kidneys. The increase of fluorine amounts in serum and in urine are not considered as adverse since no signs of toxicity was associated and since it was reversible or partially reversible (as the recovery period was only 2 week, a full reversibility was not observed for urinary fluorine); nevertheless they are related to treatment.

Torkelson et al. (1961) reported about the inhalation toxicity of boron trifluoride (CAS: 7636-07-2). Male and female rats (no data about the strain used) were offered concentrations of 3, 7.7 or 12.8 ppm for 7 h/d for 5 d/wk for up to 6 months. Analysis showed concentrations to be about one-half of these levels. The major observed effect was respiratory irritation.Toxicity also involved pneumotitis and dental fluorosis. The LOAEC was found to be 4 mg/m3 (basis: microscopically changes in the lungs characterized by the presence of areas of pneumonitis, peribronchial round cell infiltration and areas of congestion of the capillaries lining the alveolar walls).

Rusch et al. (1986) reported a two-week inhalation study with boron trifluoride dihydrate (CAS: 13319-75-0). Male and female Fischer-344-rats were offered (whole body) concentrations of 0, 24, 66 or 180 mg/m3 for 6 h/day and 5 d/week. All rats of the highest dose group died prior to the 6th exposure. No mortality occurred in the other dose groups but the animals elicited signs of respiratory distress and irritation. Mean body weight was decreased at 66 mg/m3. Lung weight was increased in all dose groups. The histopathological findings revealed a necrosis and pyknosis of the procimal tubular epithelium in the kidneys of the high exposure group rats. Nevertheless, the histopathological examination were limited. The NOAEC for systemic effects was 66 mg/m3 (tubular necrosis of the kidney). There was no apparent NOAEC for respiratory distress since it was observed at all dose levels. Nevertheless, very few detail is available on that point.

Justification for classification or non-classification

Classification proposal: EU - T; R48/23; GHS: STOT Rep. Exp. 1 (H372).