Germany is known to possess an almost odorless gas suitable for surprise attack by inclusion in
an HE bombardment from the ground or from the air. Documentary evidence shows that the Germans
refer to this gas as "Green Ring I." Here it will be called nitrogen mustard. It is only
one of several gases with similar characteristics.
It is very probable that Japan also possesses quantities of a similar gas. The plural
term "nitrogen mustards" might be used to include this whole group of odorless gases.
a. Physical Properties
In general, the nitrogen mustards are either liquids or solids with low melting points, pale
yellow to colorless, and practically without odor. Their volatility varies, some being less
volatile than mustard and some more volatile. They are fairly readily hydrolysed by water, but
products of hydrolysis are toxic. The toxicological properties of this series of compounds
are essentially similar.
Nitrogen mustard is a colorless liquid when pure, with a faint fishy odor; it is also
sometimes described as smelling like soap grease. Experiments have shown that its odor
is quite marked if the ground contamination is heavy. However, under ideal conditions, even
low concentrations can be detected by smell.
Nitrogen mustard has a low freezing point and might therefore be used for high-altitude
bombing or spray (if thickened). It is three or four times as volatile as mustard and therefore
less persistent. Since higher concentrations are possible, it is more dangerous as a gas, though
not as powerful as a vesicant It would require special stabilization if used in hot climates.
The principal danger from the nitrogen mustards is considered to be that their vapors
are not easily detected by smell. Munitions with a high bursting charge (20 to 30 percent HE) and
containing these gases are indistinguishable from HE on detonation. The nitrogen mustard
survives the detonation. By high-altitude spraying--day or night--troops might be subjected
to nitrogen mustard without knowing it. Again, troops might move into an area recently contaminated
with nitrogen mustard without suspecting its presence; or a change of wind or temperature might
result in a dangerous concentration undetectable by smell.
Under such conditions, chemical detection becomes necessary. There are three methods of detection now available.
(1) Detector paint or paper changes to bright red when in contact with liquid HS, M-1, ED, or nitrogen
mustard, but is not affected by their vapors. By exposing the detector widely and making frequent
inspection, sprayed vesicants are readily detected.
(2) The vapor-detector kit M4 will detect the presence of vapors of the various gases. It
will be of special value in cases of odorless or non-irritant toxic gases in the presence
of other odors, or in establishing the absence of any poison gas.
(3) Crayon vesicant detectors are useful in detecting definite spots of vesicants on
materiel, etc. A special crayon for nitrogen mustards is being developed, although it
is not yet standardized.
c. Physiological Effect
The effects of nitrogen mustard on the body are similar to those produced by HS. It is more
dangerous to the eyes but less vesicant on the skin. Blindness may result in from 1 to 6 hours, blistering
action may be delayed 24 hours, and death due to inhalation may be delayed as much as 4 days.
The gas mask affords a high degree of protection to face and lungs, while oilskin, rubber, and leather
give approximately the same degree of protection as against mustard gas. Standard ointments and impregnated
clothing relying on chlorination are not as effective as against HS. The greatest danger from this gas lies
in the fact that eyes and lungs may be damaged before the presence of the gas is suspected, if reliance
is placed on smell alone.
The best skin decontaminant for nitrogen mustard is soap and water. Clothing can be
decontaminated by aeration and/or washing by the standard laundry method. The protective
ointments are also effective.
For decontamination of materiel and ground, the standard methods of
bleaching (see FM 21-40 par. 25 (e) (3) ), boiling
water, or swabbing with gasoline are effective.
*The following information on odorless nitrogen mustard gases has been compiled by the Intelligence Unit
of the Chemical Warfare Service.