What happened? Police officers responded to a lab for a possible inhalation exposure to cyanogen bromide (CNBr). Police were summoned by a lab occupant at the request of a researcher who experienced respiratory irritation after he believed he had inhaled CNBr when he opened the reagent bottle in a fume hood and moved the open bottle to the face of the hood to visualize the contents. The researcher was preparing to conduct a published procedure to digest collagen using CNBr. Police summoned the fire department who later evaluated and cleared the researcher but transported him to the hospital for observation at his request. He was later discharged.
Why did it happen? Cyanogen bromide (CNBr) is a highly toxic solid that liberates a highly toxic gas, hydrogen cyanide (PDF format), on exposure to moisture, carbon dioxide or acid. CNBr is volatile and readily absorbed through the skin or gastrointestinal tract. Therefore, toxic exposure may occur by inhalation, physical contact, or ingestion. It affects the blood, cardiovascular system central nervous system and thyroid. It is also a severe eye and respiratory tract irritant and corrosive on contact.
The fume hood was evaluated and found to be properly functioning. The researcher was potentially exposed when he moved the reagent bottle to the face of the hood where containment is less effective.
How can a similar occurrence be avoided? A similar occurrence could be avoided by following proper fume hood use practices (PDF format) and the specific requirements for the use of highly toxic chemicals.
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