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CAS 20816-12-0

Osmium tetroxide

Osmium tetroxide is a highly toxic, easily evaporating oxidizer used mainly in labs for electron microscopy staining and certain chemical reactions. It matters because even tiny amounts can severely injure eyes, skin, and lungs [1][2].

Where It Comes From

Produced/used in electron microscopy and histology labs, organic synthesis, and during refining of platinum‑group metals; can form when osmium metal is oxidized [1][3].

How You Are Exposed

Mostly by breathing its vapor or getting solutions on skin/eyes in workplaces; community exposures are rare and usually from spills or accidents [1][2].

Why It Matters

Causes severe eye damage (possible vision loss), skin burns, coughing and shortness of breath; fluid in the lungs (pulmonary edema) can be delayed for hours after exposure [1][2][3].

Who Is at Risk

Lab workers (EM/histology), research and industrial chemists, metal‑refining workers, and first responders handling spills [1][3].

How to Lower Your Exposure

Use in a fume hood with closed containers; wear eye/face protection and chemical‑resistant gloves; follow workplace exposure limits and spill procedures. If a release is suspected, leave the area, get to fresh air, and seek medical help—do not handle it yourself [1][2].

References

  1. [1]ATSDR. Medical Management Guidelines for Osmium Tetroxide (OsO4), CDC.
  2. [2]CDC/NIOSH. NIOSH Pocket Guide to Chemical Hazards: Osmium tetroxide.
  3. [3]WHO IPCS/ILO. International Chemical Safety Card (ICSC) 0113: Osmium tetroxide.

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