As for mustard gas, it is extremely nasty stuff, obviously.  You can read about it here, including its effects, mode of action, etc.

For example:

Mustard gas is a powerful irritant and vesicant, used as a chemical warfare agent. The main risk of acute poisoning exists with the use of sulphur mustard vapour in war and occasionally during laboratory work. However, due to its persistence poisoning may occur at a later stage.

Target organs: Skin, eyes, respiratory tract, bone marrow.

[snip]

Nausea, fatigue, headache, eye inflammation with intense eye pain, lachrymation, blepharospasm, photophobia and rhinorrhoea, followed by reddening of face and neck, soreness of throat and increased pulse and respiratory rate develop at two to six hours post exposure.  

Six to twenty four hours post exposure the above symptoms are generally increased in severity and are accompanied by skin inflammation followed by blister formation in the warmest areas such as genito-perineal area, buttocks, axillae and on the inner aspects of thighs.

In the next twenty four hours the condition generally worsens, blistering becomes more marked, coughing appears. Mucus, pus and necrotic slough may be expectorated. Intense itching of skin and increased skin pigmentation occur.

Nice, huh?

If you look at my dailyKos post, you'll see my comment at the end that van Anraat saw footage of the Halabja attacks, and still wanted to sell thiodiglycol to Iraq.

The man has no remorse.  Too bad the law doesn't allow for a longer sentence.