This webpage is maintained by the Centers for Disease Control and Prevention (CDC). The webpage provides information and resources on Nitrogen Mustard. "Nitrogen mustards were produced in the 1920s and 1930s as potential chemical warfare weapons. They are vesicants (or blister agents) similar to the sulfur mustards. [...] Nitrogen mustards come in different forms that can smell fishy, musty, soapy, or fruity. They can be in the form of an oily-textured liquid, a vapor (the gaseous form of a liquid), or a solid. Nitrogen mustards are liquids at normal room temperature (70ºF). [...] Nitrogen mustards can be clear, pale amber, or yellow-colored when in liquid or solid form. [...] The nitrogen mustards are also known by their military designations of HN-1, HN-2, and HN-3."
Centers for Disease Control and Prevention: http://www.cdc.gov/