Editing Operation Downfall (section)

===Chemical weapons===
Fears of "an Okinawa from one end of Japan to the other"<ref name="Burnham1995">{{cite news|last=Burnham|first=Alexander|date=July 1, 1995|title=Okinawa, Harry Truman, and the Atomic Bomb|volume=71|work=A National Journal of Literature & Discussion|publisher=VQR|number=#3|url=http://www.vqronline.org/essay/okinawa-harry-truman-and-atomic-bomb|access-date=March 17, 2017}}</ref> encouraged the Allies to consider unconventional weapons, including chemical warfare. Widespread [[chemical warfare]] was considered against Japan's population<ref>{{Cite web|url=https://www.opendemocracy.net/conflict/byanymeansnecessary_2727.jsp|title=By any means necessary: the United States and Japan|last=Rogers|first=Paul|date=August 4, 2005|website=openDemocracy|access-date=July 17, 2018}}</ref> and food crops.<ref>{{cite news |last=Walsh |first=Liam |date=December 7, 2011 |title=World War II plan to poison Japanese crops revealed |url=http://m.couriermail.com.au/news/national/world-war-ii-poison-plan-revealed/story-e6freooo-1226215619956 |newspaper=the Courier-Mail |location=Australia |access-date=October 10, 2015 }}{{Dead link|date=October 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> While large quantities of gas munitions were manufactured and plans were drawn, it is unlikely they would have been used. [[Richard B. Frank]] states that when the proposal reached Truman in June 1945, he vetoed the use of chemical weapons against personnel; their use against crops, however, remained under consideration. According to [[Edward J. Drea]], the strategic use of chemical weapons on a massive scale was not seriously studied or proposed by any senior American leader; rather, they debated the ''tactical'' use of chemical weapons against pockets of Japanese resistance.<ref>{{cite web |url=https://www.pbs.org/wgbh/americanexperience/features/online-forum/ |title=Victory in the Pacific Online Forum|date=May 6, 2005 |website=[[PBS]] |access-date=October 21, 2016 }}</ref>

Although chemical warfare had been outlawed by the [[Geneva Protocol]], neither the United States nor Japan was a signatory at the time. While the US had promised never to initiate gas warfare, Japan [[Japanese war crimes#Use of chemical weapons|had used gas against the Chinese]] earlier in the war:{{sfn|Skates|p=84}}

{{blockquote|Fear of Japanese retaliation [to chemical weapon use] lessened because by the end of the war Japan's ability to deliver gas by air or long-range guns had all but disappeared. In 1944 [[Ultra (cryptography)|Ultra]] revealed that the Japanese doubted their ability to retaliate against United States use of gas. “Every precaution must be taken not to give the enemy cause for a pretext to use gas,” the commanders were warned. So fearful were the Japanese leaders that they planned to ignore isolated tactical use of gas in the home islands by the US forces because they feared escalation.{{sfn|Skates|p= 97}}|Skates}}

In addition to use against people, the U.S. military considered chemical attacks to kill crops in an attempt to starve the Japanese into submission. The Army began experimenting with compounds to destroy crops in April 1944, and within one year had narrowed over 1,000 agents to nine promising ones containing [[Phenoxy herbicide|phenoxyacetic acids]]. One compound designated LN-8 performed best in tests and went into mass production. Dropping or spraying the [[herbicide]] was deemed most effective; a July 1945 test from an SPD Mark 2 bomb, originally crafted to hold biological weapons like [[anthrax]] or [[ricin]], had the shell burst open in the air to scatter the chemical agent. By the time the war ended, the Army was still trying to determine the optimal dispersal height to cover a wide enough area. The ingredients in LN-8 and another tested compound would later be used to create [[Agent Orange]], used during the [[Vietnam War]].<ref>{{cite web |url=https://warisboring.com/the-pentagon-nearly-attacked-japan-with-chemical-weapons-in-1945-b4494e76884f#.b2wy13xdn |title=America Nearly Attacked Japan With Chemical Weapons in 1945 |last1=Trevithick |first1=Joseph |date=June 10, 2016 |website=War is Boring.com |access-date=June 11, 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160907125639/https://warisboring.com/the-pentagon-nearly-attacked-japan-with-chemical-weapons-in-1945-b4494e76884f#.b2wy13xdn |archive-date=September 7, 2016 }}</ref>