To the Editor,
I realize that I am 4 years late in coming across your article about mustard gas exposure in Louisiana in 1996,[1–4] but since I am privy to some of the litigation[5] because my major professor in chemistry at Louisiana State University was involved, I thought you might be interested. It could happen again.
The exposure was actually to tris, a well-known nitrogen mustard gas. The nitrogen mustards are cytotoxic chemotherapy agents similar to mustard gas. Although their common use is medicinal, in principle these compounds may also be used for chemical warfare purposes. The chemical formula for tris, HN3, or nitrogen mustard, is tris(2-chloroethyl) amine.
The chemical plant, Georgia-Gulf, produces some 50 tons per day of polyvinyl chloride (PVC), using ethylene and chlorine as feedstocks. Management decided to store ethylene in salt domes. This is a common procedure for storing crude oil, but apparently it was the first attempt at storing a chemical that went straight to process.
There were amounts of ammonia present that were below the plant's quality assurance/quality control standards. This quantity of ammonia is commonly found in these salt domes, and is not reactive at standard temperature and pressure conditions. However, what those at Louisiana State University and other experts opined was that the mixture of ammonia and ethylene was sent to what is referred to in chemical engineering as a “cracker” to enhance the reaction between ethylene and chlorine to make PVC.
The operating conditions of the ethylene cracker are about 220°F and between 12 and 16 pounds/square inch absolute, sufficient for the 2 chemicals to react, forming an intermediate compound, which when chlorinated formed very pure tris.
Pipelines carrying ethylene to Georgia-Gulf are unprotected for miles on both sides of the Mississippi River, and could be tapped at night by disgruntled employees who felt they did not get enough from the subsequent lawsuit.