Storage & Disposal of Sodium Nitrite Sodium nitrite is stable, and can be stored at room temperature. However, it should be stored in a sealed container. Sodium nitrite is also hygroscopic. This means that when exposed to air, it absorbs water and will slowly oxidize to sodium nitrate, silently degrading over time. Oxidization will render a sample of sodium nitrite ineffective as an end of life agent. Evidence of deterioration can be difficult to determine by visual inspection. There are no specific concerns with the disposal of any unused nitrite, and the shelf life of properly stored salt is almost infinite.
Note: Because Exit has only had detailed, monitored accounts of relatively few nitrite deaths (<50), this remains far too few to be certain that unexpected and unexplained failures using this salt may not occur. The RPA table uses a * to indicate some uncertainty.
Slide listing comparison between azide & nitrite used at Exit workshops