Barton J. Bernstein’s “Why We Didn’t Use Poison Gas in World War II” (August/September 1985) was a lucid and enlightening account of the principal factors that led both sides to abstain from the use of chemical and biological warfare.

I was somewhat surprised, however, that he did not mention the practical problems involved in the delivery of chemical and biological agents. I do not profess to be an expert in chemical and biological warfare, but I have talked to people who are, among them my instructors at the Naval Chemical and Biological Warfare School at Fort McClellan, Alabama, which I attended in 1958.

Such weapons must be delivered not only during reasonably clear weather, but also at times when there is virtually no wind. As both sides discovered in World War I, chlorine or mustard gas used in preparation for an attack often backfired with sudden shifts of wind, thereby creating more problems for the attackers than for their enemies. And even if all went well with the initial barrage, there could be trouble later. Pockets of chlorine and mustard gas were often encountered in World War I by advancing troops days after a chemical barrage had been delivered. As late as twenty years after World War I, factory sites that had produced mustard gas were found to be dangerously contaminated. If anthrax or other communicable biological weapons had been delivered against Japan, the American occupation forces would have had to control or eradicate the epidemics that they had created.

In a word, chemical and biological warfare was really practical only if used against a target that the victor did not intend to occupy.