Osmium Tetroxide Poisoning

What Is Osmium Tetroxide Chemically?

Osmium Tetroxide is a highly poisonous white to pale yellow or colorless crystalline solid with a ‘chlorine-like’ unpleasant odor at room temperature. It is a rapid and strong oxidizer and has limited solubility in water. It is a volatile solid used as a fixative in biological samples and a stain in electron microscopy. It is also used in many other industries where it is used as an industrial catalyst or oxidizing agent and for producing certain organic compounds. The synonyms are perosmic oxide, osmic acid, and osmium (Ⅳ) oxide. Osmium tetroxide is an irritant to the respiratory tract and eyes and can result in irreversible eye damage.

Some of the workers who are at risk of exposure are:

• Individuals who work in a laboratory where osmium tetroxide is used as a staining agent in electron microscopy.

• Miners who work in mines extracting osmium ore.

• In metal-working facilities that process platinum and or copper.

What Are the Different Routes of Exposure?

The different routes of exposure to Osmium tetroxide are:

• Inhalation - Breathing of aerosols or vapors can result in adverse health hazards. Osmium tetroxide in a vapor state is present in industries that refine copper. Powered osmium forms osmium tetroxide at room temperature when left exposed to air.

• Ingestion - Accidental intake of the compound can lead to adverse health effects.

• Skin Exposure - Liquids, vapors, or aerosols, when in contact with the eyes or skin, can result in adverse health effects. Liquid solutions that are used to dissolve platinum metals can produce osmium sprays.

What Are the Health Hazards?

The degree of reaction that occurs due to exposure depends on different factors like the amount of exposure, duration, and route of exposure.

Acute or Short-Term Exposure:

• Osmium tetroxide is mostly corrosive and can result in chemical burns to the respiratory tract, skin, and eyes. Acute inhalation exposure can lead to:

• Cough.

• Wheezing.

• Shortness of breath.

• Headache.

• Burning sensation.

• Pulmonary edema.

• Death (if concentration is high).

• Acute skin exposure results in:

• Skin discoloration.

• Pain.

• Skin burns.

• Blisters.

• Rash or redness.

• Black staining of skin (this occurs due to the conversion of osmium tetroxide to osmium dioxide).

Acute eye exposure results in

• Pain.

• Redness.

• Black staining of the cornea.

• Visual disturbance.

• Severe conjunctivitis.

• Permanent vision loss.

Acute ingestion exposure results in:

• Vomiting.

• Burning sensation.

• Abdominal cramps.

• Shock.

Chronic or Long-term Exposure:

• Low-level inhalation exposure for a long period results in:

• Digestive disturbances.

• Sleep disturbances.

• Prolonged skin contact leads to skin inflammation or dermatitis.

• Mild kidney damage, especially in those with pre-existing kidney disorders.

• Lung irritation may lead to bronchitis.

• Some animal studies suggest that chronic exposure may result in mutations and reproductive hazards, but further studies are needed.

What Are the First Aid Measures to Be Taken in Case of Exposure?

• Eye Contact: Remove contact lenses, if any. Flush the eyes with running water for a minimum period of 15 minutes. Flush with cold running water, keeping the eyelids open. Avoid using eye ointment. Get immediate medical attention.

• Inhalation - If a large amount has been inhaled and the affected shows signs of exposure, move the victim to a well-ventilated area and seek immediate medical attention.

• Skin Contact - In case of skin exposure, wash with plenty of water and non-abrasive soap. Be careful in cleaning the groin, crevices, creases, and folds. The irritated skin is covered with an emollient. In case of serious skin contact, cover with anti-bacterial cream and seek immediate care.

• Ingestion - In case of ingestion, vomiting should not be induced. Rinse the mouth thoroughly with water. Look for signs of tissue damage by examining the mouth and lips. Loosen any tight clothing. Seek immediate medical care.

How Is the Exposure Managed?

Management of osmium tetroxide poisoning involves removing the victim from the source of exposure. Osmium tetroxide is removed from clothing, skin, and mucous membranes as far as possible, and supportive medical care is given. However, there is no antidote for the poisoning.

What Are the Precautions That Can Be Taken to Minimize Exposure?

Engineering Control - Engineering control options are the most effective way to reduce exposure.

• The work that involves osmium tetroxide should only be carried out in a certified chemical hood.

• In case of unavoidable work to be carried out outside the hood, respiratory protection is required.

• Local exhaust ventilation should be provided at the site of chemical release.

• The lab should have 100 percent exhaust.

• Osmium tetroxide should be automatically transferred from storage to process containers.

• The safety shower and eyewash should be operational.

• Keep containers closed when not in use.

• Spills should be cleaned immediately.

• Work surfaces should be protected with plastic-backed absorbent pads.

Follow Good Work Practices - Following good work practices reduces exposure:

• In case of cloth contamination by osmium tetroxide, immediately change the clothing.

• Avoid taking contaminated clothing outside the laboratory.

• In case of skin exposure, immediately shower to remove the chemical.

• Avoid drinking, eating, or smoking inside the laboratory where the chemical is processed, as there is a chance for ingestion.

• Use a vacuum or wet method for dust removal and avoid dry sweep-up.

Personal Protective Equipment - The main aim of using personal protective equipment is to avoid skin and eye exposure to the chemical. Any exposed skin with a chance to contact the chemical should be covered.

• Chemically resistant buttoned laboratory coat.

• Full-length skirts or pants.

• Face shields and safety goggles should be used while mixing large volumes of concentrated solutions.

• Closed-toed shoes.

• Use double gloves or gloves as per the manufacturer’s recommendation. Avoid latex gloves.

• Gloves must be frequently changed and disposed of immediately once they get contaminated.

Storage Recommendations - Storage recommendations to minimize exposure are:

• Pure and concentrated solutions of osmium tetroxide should be stored in appropriately sealed glass containers placed within unbreakable secondary containment.

• All contaminants should be labeled with hazard warnings and the chemical name.

Waste Disposal - The osmium-containing waste products must be placed in properly sealed and labeled hazardous waste containers.

• A neutralization procedure should be done to reduce hazards associated with chemical disposal.

• The neutralization procedure should be done in a chemical hood.

Conclusion

Osmium tetroxide is a hazardous volatile white or crystalline solid with an unpleasant odor. It is mainly used as a fixative and for electron microscopy as a stain. Poisoning can result in various health hazards. There is no antidote for poisoning, and management mainly involves supportive care and chemical removal. Proper precautionary measures should be followed by the industries and the personnel who work in such industries related to the use of osmium tetroxide.