The toxic properties of sodium azide, its instability, storage difficulties, and its use in the manufacture of explosives mean that the substance is subject to some control, but less than those applied to the cyanide salts.
The speed and reliability of a death from ingestion of sodium azide make this salt an effective option, Indeed, the toxicological report commissioned by CLW is clear in its conclusion that this substance is a useful end of life agent.
The lack of any antidote is seen by CLW as an important positive aspect of its use. Although this is only really significant if there is a high prospect of emergency intervention.
There remain several unpleasant symptoms that may develop prior to loss of consciousness and that can be difficult to address. The problems associated with the storage, safe disposal, and the risk it poses to others after death also limit the usefulness of sodium azide.
That said, sodium azide is an important available substance that provides a lawful, end of life option for those who have no access to the barbiturate, Nembutal.