[1] It is an oily liquid with a colorless to pale yellow appearance and a faint fishy or musty odor.

At pH 8, the nitrogen mustards are essentially quantitatively converted to the aziridinium ion for subsequent slow reaction with water.

Eye exposure to vapor can cause lacrimation (tears), blepharospasm (eyelid twitching), irritation, itching, burning pain, dry feeling, and sometimes miosis (pinpoint pupils).

More severe vapor exposure can also cause swelling and fluid buildup (edema) in the eyelids, increased pain, and redness.

Mild inhalation exposure causes rhinorrhea (runny nose), sneezing, barking cough (a harsh cough that sounds somewhat like a dog barking), epistaxis (nosebleed), dyspnea (shortness of breath) that affects smokers and asthmatics, hoarseness that turns into toneless voice, ageusia (loss of taste), and anosmia (loss of smell); later on, sinus and nose pain develops.

[1] Skin contact with nitrogen mustard in low concentrations causes symptoms beginning with redness, then moving to blistering, itching, and burning pain.

Though ingestion is uncommon, nitrogen mustard can burn the GI tract and cause nausea, vomiting, hemorrhagic diarrhea, and abdominal pain.

Other consequences of acute exposure include ageusia, anosmia, pulmonary fibrosis, scarring, bronchitis, chronic respiratory disease, mental illness, and central nervous system damage.

If HN1 has been ingested, emetics (agents that induce vomiting) and gastric lavage are contraindicated, and nothing should be consumed by mouth because they could damage the gastrointestinal system.