Area of Science:

• Occupational Health
• Materials Science
• Pulmonary Medicine

Background:

• Calcined diatomaceous earth, containing crystalline silica like cristobalite, poses a silicosis risk.
• This risk is often underestimated in dental alginate production and use.
• Past cases of severe silicosis have been linked to occupational exposure to transformed amorphous silica.

Observation:

• A case study investigated a worker in dental alginate production with severe silicosis.
• Analysis of calcined diatomaceous earth revealed high cristobalite concentrations (36%).
• Necropsy revealed significant diatom fragments and cristobalite in lung tissues.

Findings:

• Material Safety Data Sheets (MSDS) showed discrepancies in reporting cristobalite content and silicosis risk over time.
• An older MSDS (2002) reported up to 63% silica with cristobalite, while a newer one (2018) indicated less than 1% cristobalite and no risk.
• The worker developed severe silicosis, confirmed by necropsy, which contributed to their death.

Implications:

• The study highlights ignored silicosis risks associated with calcined diatomaceous earth in dental alginate manufacturing.
• Inadequate engineering controls and personal protective measures contributed to severe lung disease.
• Current safety data sheets may fail to adequately communicate the hazards of crystalline silica in commercial products.