HD can cause severe blisters on the skin and in the respiratory system. This mustard agent can be long lasting under normal environmental conditions. In appearance, HD looks like heavy motor oil, but it can be turned into a mist. Exposure is usually not fatal. The primary hazard of HD is liquid exposure to the skin.
Nerve agents affect the nervous system.
GB has a water-like consistency. It evaporates rapidly and dissipates quickly in the environment. Therefore, the primary hazard associated with GB is vapor inhalation. VX is a thick liquid that has a consistency of motor oil. It is intended to be spread in fine droplets, like a mist.