On July 3 of this year an old lecture bottle of hydrogen fluoride exploded in a chemistry lab at UC Santa Barbara. The attached picture shows the remains of the lecture bottle.

Anhydrous hydrogen fluoride slowly reacts over time with the iron in the steel to form iron fluoride and hydrogen. The hydrogen pressure can ultimately build to the point where it ruptures the cylinder. This is discussed more fully on this link from Air Products.

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Please dispose of anhydrous hydrogen fluoride lecture bottles that are more than 2 years old.