Phosphine is a highly toxic, flammable, colorless
gas with an odor similar to that of decaying fish. The odor is subjective
and therefore not reliable, and should not be used to detect the presence
of the gas. It is subject to spontaneous combustion. Phosphine is
shipped as a liquefied gas under its own vapor presure.
Flammability Limits in air
Gas @ 70°F(21.1°C),