Accounts by U.S. veterans in the accompanying feature of tons of chemical weapons being dumped off Okinawa in autumn 1969 are the first time such revelations have been made public — but in fact they tally entirely with the Pentagon's standard operating procedures at that time.

For almost as long as such weapons have been in existence, there has been a problem of what to do with them when they leaked or were rendered obsolete by new munitions. With incineration generally too dangerous due to the risk of toxic smoke, and burial requiring large tracts of land, the sea has often appeared to the military to be the ideal dumpsite — free, immense and hopefully able to render poisons harmless by diluting them.

Following World War I, the Allied forces dropped stockpiles of captured German blister chemicals — mustard agent and lewisite — into the Mediterranean and the Atlantic Ocean. Then after World War II, the United States staged similar dumps of the Imperial Japanese Army's stocks of some 6,600 tons of munitions — including mustard agent and hydrogen cyanide, a potent asphyxiant. According to records held by the Ministry of the Environment in Tokyo, disposal was at more than 20 sites off Tokyo and Ibaraki and Hiroshima prefectures.