In reply to the Duke of Pearl, here's some scientific evidence that breathing lots of dust from seashells can make you quite sick, sometimes irreversibly so. The initial problem is hypersensitivity pneumonitis; useful overview is at UCSF's Hypersensitivity Pneumonitis Treatment pageIt's worth informing yourself about how to stay healthy when working with seashell-based materials.
Three medical-journal articles, all at movingforwardtogether.info/4.html include: 1) Orriols R, Aliaga JL, Anto JM, Ferrer A, Hernandez A, Rodrigo MJ, et al. "High prevalence of mollusc shell hypersensitivity pneumonitis in nacre factory workers." European Respiratory Journal 1997 Apr;10(4):780-786 "Following the discovery of hypersensitivity pneumonitis caused by the inhalation of mollusc shell dust in two workers from a nacre-button factory, the health status of 26 workers employed in sawing mollusc shells was investigated. ...Six workers, in whom specific inhalation challenge test was positive, were diagnosed with mollusc shell hypersensitivity pneumonitis, thus yielding a prevalence of 23%. Evidence of diffuse lung disease and systemic symptoms was found in these patients. Nonspecific bronchial hyperreactivity was also found more frequently in patients with mollusc shell hypersensitivity pneumonitis. ...The clinical picture of the 20 workers who did not present mollusc shell hypersensitivity pneumonitis remained unchanged, but functional decline was observed despite improvement in the environmental conditions of the factory. This report describes the first series of patients with mollusc shell hypersensitivity pneumonitis studied, and underlines the importance of careful follow-up of workers occupationally-exposed to mollusc shell dust. PMID9150313."
2) Orriols R, Aliaga JL, Anto JM, Ferrer A, Hernandez A, Rodrigo MJ, et al. "High prevalence of mollusc shell hypersensitivity pneumonitis in nacre factory workers." Eur.Respir.J. 1997 Apr;10(4):780-786 "... This report describes two patients with hypersensitivity pneumonitis caused by inhalation of sea shell dust; both women worked in a button factory cutting sea-snail shells into disks. After exposure to the dust, the two non-smoking patients developed a dry cough, fever, lack of strength and pain upon breathing. Accompanying these symptoms was a weight loss of 16 and 40 pounds, respectively. Chest x-rays that allow visualization of the lungs showed the development of lung nodules in both patients. Their conditions improved after a three-month absence from work. Both women had antibody levels against the sea-shell dust that were much higher than in the normal population. ..."
3) Weiss W, Baur X. "Antigens of powdered pearl-oyster shell causing hypersensitivity pneumonitis". Chest journal 1987 Jan;91(1):146-148 We describe the identification and characterization of antigens of the pearl-oyster shell which caused hypersensitivity pneumonitis in a 42-year-old worker. He was occupationally exposed to the dust of this shell in the manufacture of different ornaments..."
Anyone who has ever worked in this industry knows this, and those who deny it are either only fooling themselves or trying to avoid lawsuits. If nothing else the dust is sharp edged and physically damages lung tissue.
I bought some abalone shells when i first started making banjos. I ground them with a belt sander. I got terrible fever and chills and nausea. The first time, I didn't know what was wrong with me. After two more time with the same symptoms, i figured out it was the pearl dust. I stopped grinding pearl. When i cut pearl, I soak it in water and vacuum or wash away any dust as i cut.
Oh yeah, you don't want that, kind of like asbestos, very minute particles that cling to the walls of your lungs and cannot be removed. I always use a mask, and a small vacuum with hose right by my work