Occupational exposure to beryllium is well-documented to put workers’ health at risk. The two principal targets of beryllium poisoning are the respiratory system and the skin. Of all beryllium compounds, beryllium fluoride complexes (including beryllium fluoride and beryllium oxyfluoride) appear to be the most toxic.

As shown below, studies dating back to the 1930s have clearly shown that beryllium fluoride compounds have a much greater systemic toxicity, and produce more severe respiratory and dermatological (skin) reactions at lower concentrations, than other common beryllium compounds.

Based on the evidence, it is apparent that workers exposed to a combination of beryllium and fluoride dusts will be more vulnerable to “beryllium poisoning” than workers exposed to beryllium dusts that do not contain fluoride. Despite this fact, most of the literature discussing occupational beryllium poisoning fails to discuss the often contributing/potentiating role of fluoride dusts..

While fluoride is a powerful respiratory irritant in and of itself, it appears that fluoride’s ability to potentiate the toxicity of beryllium may result from the beryllium fluoride complex’s capacity to mimic g-proteins, thereby enabling both beryllium and fluoride to penetrate deeper into tissue and cells.

1. Systemic Toxicity:

“Having regard to the differential lethal doses of these compounds, BeF2 (beryllium fluoride) was judged to be appreciably more poisonous than BeHPO4… The marked tissue reaction to BeF2 contrasts sharply with the responses to the equivalent low aerosol concentrations of BeSO4 and BeHPO4… When one reviews the extrathoracic responses to the inhaled beryllium aerosols, the contrast between the multiplicity of effects of exposure to BeF2 and the paucity of systemic responses to BeSO4 and BeHPO4 are particularly striking… Since BeF2 proved so excessively toxic one may wonder whether the fluorine radicle was a factor in the genesis of the pulmonary and systemic lesions induced by inhalation of low concentrations of this compound. Solubility does not furnish the explanation since BeSO4 was about equally soluble.”
SOURCE: Schepers GWH. (1964). Biological action of beryllium: Reaction of the monkey to inhaled aerosols. Industrial Medicine and Surgery 33: 1-16.

“The results of these studies clearly indicate that beryllium fluoride is acutely more toxic than either the sulfate or the oxide of this metal. Whereas exposure of seven species of animals to 10 mg/m3 of beryllium sulfate for 95 days proved lethal to only rats, significant mortality occurred among dogs, guinea pigs, mice, and rats exposed to the same concentration of beryllium fluoride for only 15 days. No deaths occurred among dogs exposed to 10 mg/m3 of beryllium oxide dust for 40 days. Comparing the mortalities during exposure to a concentration of approximately 1 mg/m3, beryllium sulfate caused no deaths among seven species in a period of 100 days, whereas three dogs exposed to beryllium fluoride died after 29, 56, and 70 days, respectively… After exposure to 10 mg/m3 of beryllium fluoride, the severity of the pulmonary lesions was about equivalent to that seen in animals of the same species exposed to 50 to 100 mg/m3 of beryllium sulfate… In relation to the quantity of beryllium in the lungs, a considerably greater proportion was distributed to the skeleton, liver, spleen, and kidneys of dogs after inhalation of beryllium fluoride than was found in previous studies of the insoluble beryllium oxide or the soluble and readily dissociated beryllium sulfate mist.”
SOURCE: Stokinger HE, et al. (1953). Acute inhalation toxicity of beryllium. IV. Beryllium fluoride at exposure concentrations of one and ten milligrams per cubic meter. AMA Archives of Industrial Hygiene and Occupational Medicine 8(6): 493-506.

“The potentially toxic dusts or vapors encountered in industrial processes are frequently not single compounds but mixtures of various substances. An example is provided in the manufacture of beryllium, in which hydrogen fluoride (HF) or other fluorides have been shown not only to be present but actually to exist in amounts several hundred fold greater than that of beryllium… The study described in the following pages was performed to determine whether hydrogen fluoride has a potentiating effect on beryllium poisoning by inhalation. The results obtained in rats confirm this hypothesis. Such results have obvious implications in industrial exposures… The self-consistent and definitive results in mortality, weight response and pathologic changes leave no doubt as to the enhancing effect of hydrogen fluoride on beryllium sulfate poisoning by inhalation in rats. The mechanism by which this occurs is far from understood. It is possible that fluoride combines with beryllium in vivo, producing a more toxic compound, beryllium fluoride (BeF2), or produces some related fluorine compound more toxic than is the original beryllium sulfate inhaled. Inhalation experiments have been performed that show beryllium fluoride to be more toxic than beryllium sulfate, weight for weight compound. Some such explanation is consistent also from the finding of increased fluoride content of bone and tooth in animals exposed to beryllium in the presence of hydrogen fluoride, the fluoride content of the bone appearing to be influenced by the presence of beryllium. Certainly beryllium fluoride is a far less dissociated compound than is beryllium sulfate, and in consequence it is reasonable to suppose that the compound may have a toxicity characteristic of the molecule as a whole rather than of the beryllium ion alone.”
SOURCE: Stokinger HE, et al. (1950). Acute inhalation toxicity of beryllium. II. The enhancing effect of the inhalation of hydrogen fluoride vapor on beryllium sulfate poisoning in animals. Archives of industrial hygiene and occupational medicine 1:398-410.

“Beryllium poisoning is an industrial disease that demands attention because of the loss in manpower and the fatalities incident to increased production in the beryllium industry. During the past four years 170 cases of poisoning were seen among workers in three plants producing beryllium, its compounds and its alloys. Manifestations included dermatitis, chronic skin ulcer and inflammatory changes in the respiratory tract, skin and respiratory tract changes occurring concurrently or singly… The specific etiology of beryllium poisoning is not known. Apparently manifestations can be caused by several beryllium compounds, severity of symptoms being dependent on amount of exposure, toxicity and concentration of the substance, and possible individual sensitivity. In this study patients employed in the sulfating and the oxyfluoride process showed the highest incidence of the disease.”
SOURCE: VanOrdstrand HS, DeNardi JM, Carmody MG. (1945). Beryllium poisoning. Journal of the American Medical Association 129: 1084-1090.

2. Respiratory Damage

“Dyspnea… developed most rapidly in the monkeys in the BeF2 chamber, and on continued exposure they suffered marked air hunger.”
SOURCE: Schepers GWH. (1964). Biological action of beryllium: Reaction of the monkey to inhaled aerosols. Industrial Medicine and Surgery 33: 1-16.

“After exposure to 10 mg/m3 of beryllium fluoride, the severity of the pulmonary lesions was about equivalent to that seen in animals of the same species exposed to 50 to 100 mg/m3 of beryllium sulfate.”
SOURCE: Stokinger HE, et al. (1953). Acute inhalation toxicity of beryllium. IV. Beryllium fluoride at exposure concentrations of one and ten milligrams per cubic meter. AMA Archives of Industrial Hygiene and Occupational Medicine 8(6): 493-506.

“That hazards to health attend the production of beryllium oxide at this plant becomes evident by only a cursory examination of the records of the medical cases reporting to the plant physician… The facts that employees exposed to fluorides in the plant have been and still are reporting with respiratory diseases and dermatitis and that these illnesses are more frequent than any others, indicate that the fluorides are a very likely source of the trouble. Fluorine, which is a strong irritant, assumes an important role in the extraction of beryllium oxide from its ore… The concentration of hydrogen fluoride permissible in the air has been generally accepted and stated as three parts per million parts of air…[A] serious doubt has arisen in our minds as to the correctness of such a standard… [T]he concentrations are, with few exceptions, well below this limit. But illnesses continue among the employees at the plant in question at the concentrations found… It is, therefore, our opinion that the atmospheric concentration of sodium fluoride should be reduced to 0.2 mg. of sodium fluoride (equivalent to 0.0952 mg hydrogen fluoride and 0.0904 mg. fluorine), or less, per cubic meter in order to preven sickness or health injury.”
SOURCE: Shilen J, Galloway AE, Mellor JF. (1944). Beryllium oxide from beryl – Health hazards incident to extraction. Industrial Medicine 13: 464-469.

“The mechanism of poisoning by beryllium oxyfluoride is not represented simply by the sum of the actions of beryllium and fluorine… [T]he rupturing action of fluorine, penetrating into the alveoli with missile-like force without retention in the upper respiratory tract. The action of the fluorine in such conditions is especially strong and prolonged, which fact conditions the specificity of the picture of poisoning by beryllium oxyfluoride… Since the toxic action of beryllium oxyfluoride differs markedly from that of oxides of nitrogen and chlorine and to a less extent from that of mustard gas, it becomes necessary to assume a different mechanism of action. We suppose that the protracted action of beryllium fluoride is conditioned by the fixation of this poison in the alveoli and bronchioles. It is necessary to consider that beryllium oxyfluoride, coming into contact with the alveoli and bronchioles, splits up at just this point into beryllium oxide and fluorine. The molecule of beryllium oxyfluoride is, as it were, a charge bursting in the alveoli and here liberating on the one hand particles of beryllium oxide in a dispersed phase and on the other, fluorine. Thus we have a kind of explosive action with the formation of fluorine in statu nascendi. Hence the deeper and, most important, more prolonged action of this gas in comparison with that which we see following the inhalation not only of oxides of nitrogen and chlorine but also vapors of fluorine or hydrofluoric acid.”
SOURCE: Gelman I. (1936). Poisoning by vapors of beryllium oxyfluoride. Journal of Industrial Hygiene and Toxicology 18: 371-379.

3. Dermatitis:

“An allergic contact dermatitis can occur and is most frequently caused by beryllium fluoride.”
SOURCE: Agency for Toxic Substances and Disease Registry. (1993). Toxicological Profile for Beryllium. US Department of Health and Human Services, Public Health Service.

“It was again noted that the more soluble BeF2 produced a reaction larger than that produced by BeSO4 and in turn larger than the reaction produced at the BeO test site.”
SOURCE: Marx JJ, Burrell R. (1973). Delayed hypersensitivity to beryllium compounds. Journal of Immunology 111: 590-598.

“Dermatitis caused by beryllium compounds is one of the principal occupational hazards in beryllium-extraction plants… De Nardi (1950) reported 202 cases of dermatitis… from two beryllium-extraction plants near Cleveland during the period from 1940 to Jan 17, 1940. Of the 202 cases of dermatitis, De Nardi lists 156 as due to beryllium fluoride (BeF2) and 45 as due to beryllium sulfate… Of the 13 patients discussed in this report, the dermatitis was caused by BeF2 in 10… It is immediately apparent that the results of quantitative patch tests show a variation in the capacity of the compounds to elicit the degree of severity of the reaction. The sequence is BeF2 > BeSO4 = BeCl2 > Be(NO3)3… BeF2 exceeds BeSO4 and BeCl2 in both the capacity to sensitize and the capacity to elicit a greater degree of severity of reaction… [T]he incidence of dermatitis caused by BeF2 is almost four times that caused by BeSO4, although a much larger number of workers are employed in the sulfate method of beryllium extraction… Beryllium fluoride possesses the capacity to sensitize the skin to a high degree, which accounts for the high incidence of dermatitis among workers in the fluoride process of beryllium extraction. Beryllium sulfate and beryllium chloride have less capacity than beryllium fluoride to sensitize the skin, while beryllium nitrate was found to have little or no capacity to sensitize the skin…”
SOUCE: Curtis GH. (1951). Cutaneous hypersensitivity due to beryllium. AMA Archives of Dermatology and Syphilology 64: 470-482.

“That hazards to health attend the production of beryllium oxide at this plant becomes evident by only a cursory examination of the records of the medical cases reporting to the plant physician… The facts that employees exposed to fluorides in the plant have been and still are reporting with respiratory diseases and dermatitis and that these illnesses are more frequent than any others, indicate that the fluorides are a very likely source of the trouble. Fluorine, which is a strong irritant, assumes an important role in the extraction of beryllium oxide from its ore… The concentration of hydrogen fluoride permissible in the air has been generally accepted and stated as three parts per million parts of air…[A] serious doubt has arisen in our minds as to the correctness of such a standard… [T]he concentrations are, with few exceptions, well below this limit. But illnesses continue among the employees at the plant in question at the concentrations found… It is, therefore, our opinion that the atmospheric concentration of sodium fluoride should be reduced to 0.2 mg. of sodium fluoride (equivalent to 0.0952 mg hydrogen fluoride and 0.0904 mg. fluorine), or less, per cubic meter in order to preven sickness or health injury.”
SOURCE: Shilen J, Galloway AE, Mellor JF. (1944). Beryllium oxide from beryl – Health hazards incident to extraction. Industrial Medicine 13: 464-469.

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