A NIOSH health-hazard evaluation at a polypropylene manufacturing plant characterized polypropylene powder and reviewed worker health concerns; the report states that pure polypropylene is generally considered inert and did not establish a causal link between inhaled calcium-dust additive and kidney stones.
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page 6 · Evaluation Results and Discussion — Medical · 3
page 6 · Evaluation Results and Discussion — Medical · 3
One employee ... was concerned that his kidney stone problem may have been precipitated by exposure to the calcium stearate additive he routinely handles in dust form. There is no evidence linking inhalation of calcium dust to stone formation.