Acetic Acid
Working Safely

Acetic acid is not a major safety concern in histology laboratories. Although consumed in foods, solutions of acetic acid much stronger than the 5% or less found in vinegar can cause burns, and the concentrated acid must always be treated with respect and handled carefully. Although it is a weak acid, that is a reference to how it ionises and is not a comment on whether it can cause burns or not. It can when spilt on the skin and it can burn the mouth if a too high concentration is ingested, as with faulty pipetting. Use standard laboratory practices when measuring glacial acetic acid in the same way as you would when measuring concentrated hydrochloric acid.

Spills may be flooded with water to dilute the acid, then mopped up with towels and discarded. There are no restrictions, usually, about disposal through municipal waste water systems, although it is as well to check local regulations. Just ensure that plenty of water is used to flush it away.

It is often not realised that glacial acetic acid is flammable. It will burn with a pale blue flame if ignited. Unfortunately, this flame is difficult to see and it is easy to pass an arm over it should some acid be ignited. Always look carefully at the surface of an open container of the glacial acid to ensure it is safe to handle.



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