Editing Chemical warfare (section)

===United States===
{{See also|United States and weapons of mass destruction#Chemical weapons}}
On November 25, 1969, President [[Richard Nixon]] [[Statement on Chemical and Biological Defense Policies and Programs|unilaterally renounced the offensive use of biological and toxic weapons]], but the U.S. continued to maintain an offensive chemical weapons program.<ref name=CaseStudy1>Jonathan B. Tucker & Erin R. Mahan, [https://ndupress.ndu.edu/Portals/68/Documents/casestudies/CSWMD_CaseStudy-1.pdf Case Study 1: President Nixon's Decision to Renounce the U.S. Offensive Biological Weapons Program], Case Studies Series, Center for the Study of Weapons of Mass Destruction, National Defense University (October 2009).</ref>

From May 1964 to the early 1970s the U.S. participated in [[Operation CHASE]], a [[United States Department of Defense]] program that aimed to dispose of chemical weapons by sinking ships laden with the weapons in the deep Atlantic. After the [[Marine Protection, Research, and Sanctuaries Act of 1972]], Operation Chase was scrapped and safer disposal methods for chemical weapons were researched, with the U.S. destroying several thousand tons of sulfur mustard by incineration at the [[Rocky Mountain Arsenal]], and nearly 4,200 tons of nerve agent by chemical neutralisation at [[Tooele Army Depot]].<ref>{{cite web|url=http://www.epa.gov/region8/superfund/co/rkymtnarsenal/ |title=Rocky Mountain Arsenal &#124; Region 8 &#124; US EPA |publisher=Epa.gov |access-date=September 16, 2011}}</ref>

The U.S. began stockpile reductions in the 1980s with the removal of outdated munitions and destroying its entire stock of [[3-Quinuclidinyl benzilate]] (BZ or Agent 15) at the beginning of 1988. In June 1990 the [[Johnston Atoll Chemical Agent Disposal System]] began destruction of chemical agents stored on the [[Johnston Atoll]] in the Pacific, seven years before the Chemical Weapons Treaty came into effect. In 1986 President Ronald Reagan made an agreement with [[Chancellor of Germany|German Chancellor]] [[Helmut Kohl]] to remove the U.S. stockpile of chemical weapons from Germany. In 1990, as part of [[Operation Steel Box]], two ships were loaded with over 100,000 shells containing [[Sarin]] and [[VX (nerve agent)|VX]] were taken from the U.S. Army weapons storage depots such as Miesau and then-classified FSTS (Forward Storage / Transportation Sites) and transported from Bremerhaven, Germany to Johnston Atoll in the Pacific, a 46-day nonstop journey.<ref>The Oceans and Environmental Security: Shared U.S. and Russian Perspectives.</ref>

In the 1980s, Congress, at the urging of the [[Reagan administration]], Congress provided funding for the manufacture of [[binary chemical weapon]]s (sarin artillery shells) from 1987 until 1990, but this was halted after the U.S. and the [[Soviet Union]] entered into a [[1990 Chemical Weapons Accord|bilateral agreement in June 1990]].<ref name=CaseStudy1/> In the 1990 agreement, the U.S. and Soviet Union agreed to begin destroying their chemical weapons stockpiles before 1993 and to reduce them to no more than 5,000 agent tons each by the end of 2002. The agreement also provided for exchanges of data and inspections of sites to verify destruction.<ref name=Glass>Andrew Glass, [https://www.politico.com/story/2017/06/01/deal-reached-curbing-chemical-weapons-june-1-1990-238946 Deal reached curbing chemical weapons, June 1, 1990], ''Politico'' (June 1, 2017).</ref> Following the [[collapse of the Soviet Union]], the U.S.'s [[Nunn–Lugar Cooperative Threat Reduction]] program helped eliminate some of the chemical, biological and nuclear stockpiles of the [[former Soviet Union]].<ref name=Glass/>

The [[United Nations]] [[Conference on Disarmament]] in [[Geneva]] in 1980 led to the development of the [[Chemical Weapons Convention]] (CWC), a [[multilateral treaty]] that prohibited the development, production, stockpiling, and use of chemical weapons, and required the elimination of existing stockpiles.<ref name=Tucker>Jonathan B. Tucker, [https://wmdcenter.ndu.edu/Portals/97/Documents/Publications/Case%20Studies/CSWMD-Case-Study-4.pdf Case Study 4, U.S. Ratification of the Chemical Weapons Convention], ''Case Studies Series'', Center for the Study of Weapons of Mass Destruction, [[National Defense University (Washington, D.C.)|National Defense University]] (December 2011).</ref> The treaty expressly prohibited state parties from making [[Reservation (law)|reservations]] (unilateral caveats).<ref name=Tucker/> During the Reagan administration and the George H. W. Bush administration, the U.S. participated in the negotiations toward the CWC.<ref name=Tucker/>  The CWC was concluded on September 3, 1992, and opened for signature on January 13, 1993. The U.S. became one of 87 original state parties to the CWC.<ref name=Tucker/>  President [[Bill Clinton]] submitted it to the [[U.S. Senate]] for ratification on November 23, 1993. Ratification was blocked in the Senate for years, largely as a result of opposition from Senator [[Jesse Helms]], the chairman of the [[Senate Foreign Relations Committee]].<ref name=Tucker/> On April 24, 1997, the Senate gave its consent to ratification of the CWC by a 74–26 vote (satisfying the required two-thirds majority). The U.S. deposited its instrument of ratification at the United Nations on April 25, 1997, a few days before the CWC entered into force. The U.S. ratification allowed the U.S. to participate in the [[Organisation for the Prohibition of Chemical Weapons]], the organization based in [[The Hague]] that oversees implementation of the CWC.<ref name=Tucker/>

Upon U.S. ratification of the CWC, the U.S. declared a total of 29,918 tons of chemical weapons, and committed to destroying all of the U.S.'s chemical weapons and bulk agent.<ref name=LeGrone>Owen LeGrone, [https://www.armscontrol.org/act/2019-07/news/us-begins-final-cw-destruction U.S. Begins Final CW Destruction], ''Arms Controls Today'', Arms Control Association (July/August 2019).</ref> The U.S. was one of eight states to declare a stockpile of chemical weapons and to commit to their safe elimination.<ref name=ProgressUpdate>[https://www.armscontrol.org/events/2021-09/us-chemical-weapons-stockpile-elimination-progress-update US Chemical Weapons Stockpile Elimination: Progress Update], Arms Control Association (September 23, 2021).</ref> The U.S. committed in the CWC to destroy its entire chemical arsenal within 10 years of the entry into force (''i.e.'', by April 29, 2007),<ref name=LeGrone/>  However, at a 2012 conference,<ref name=CDCCWElimination>[https://www.cdc.gov/nceh/demil/history.htm History of U.S. Chemical Weapons Elimination], Centers for Disease Control and Prevention (January 6, 2014).</ref> the parties to the CWC parties agreed to extend the U.S. deadline to 2023.<ref name=LeGrone/><ref name=CDCCWElimination/> By 2012, stockpiles had been eliminated at seven of the U.S.'s nine chemical weapons depots and 89.75% of the 1997 stockpile was destroyed.<ref name="Complete">[http://www.cma.army.mil/fndocumentviewer.aspx?DocID=003683880 Army Agency Completes Mission to Destroy Chemical Weapons] {{Webarchive|url=https://web.archive.org/web/20120915082045/http://www.cma.army.mil/fndocumentviewer.aspx?DocID=003683880 |date=September 15, 2012 }}, USCMA, January 21, 2012</ref> The depots were the [[Aberdeen Chemical Agent Disposal Facility]], [[Anniston Chemical Activity|Anniston Chemical Disposal Facility]], [[Johnston Atoll]], [[Newport Chemical Agent Disposal Facility]], [[Pine Bluff Chemical Activity|Pine Bluff Chemical Disposal Facility]], [[Tooele Chemical Agent Disposal Facility|Tooele Chemical Disposal Facility]], [[Umatilla Chemical Depot|Umatilla Chemical Disposal Facility]],<ref name=CDCCWElimination/> and [[Deseret Chemical Depot]].<ref name="Complete"/> The U.S. closed each site after the completion of stockpile destruction.<ref name=CDCCWElimination/> In 2019, the U.S. began to eliminate its chemical-weapon stockpile at the last of the nine U.S. chemical weapons storage facilities: the [[Blue Grass Army Depot]] in Kentucky.<ref name=LeGrone/> By May 2021, the U.S. destroyed all of its Category 2 and Category 3 chemical weapons and 96.52% of its Category 1 chemical weapons.<ref name=ProgressUpdate/> The U.S. is scheduled to complete the elimination of all its chemical weapons by the September 2023 deadline.<ref name=LeGrone/> In July 2023 OPCW confirmed the last chemical munition of the U.S., and that the last chemical weapon from the stockpiles declared by all States Parties to the Chemical Weapons Convention was verified as destroyed.<ref>{{cite web |title=OPCW confirms: All declared chemical weapons stockpiles verified as irreversibly destroyed |url=https://www.opcw.org/media-centre/news/2023/07/opcw-confirms-all-declared-chemical-weapons-stockpiles-verified |publisher=OPCW |access-date=9 July 2023}}</ref>

The U.S. has maintained a "[[Strategic ambiguity|calculated ambiguity]]" policy that warns potential adversaries that a chemical or biological attack against the U.S. or its allies will prompt a "overwhelming and devastating" response. The policy deliberately leaves open the question of whether the U.S. would respond to a chemical attempt with [[nuclear weapon|nuclear]] [[Massive retaliation|retaliation]].<ref name=Conley>{{cite journal |author=Harry W. Conley |url=http://www.airpower.maxwell.af.mil/airchronicles/apj/apj03/spr03/conley.html |title=Not with Impunity: Assessing US Policy for Retaliating to a Chemical or Biological Attack |journal=Air & Space Power Journal |date=Spring 2003 |volume=17 |issue=1 |publisher=Air University Press |archive-url=https://web.archive.org/web/20131203201729/http://www.airpower.maxwell.af.mil/airchronicles/apj/apj03/spr03/conley.html |archive-date=3 December 2013 |url-status=dead}}</ref> Commentators have noted that this policy gives policymakers more flexibility, at the possible cost of decreased strategic unpreparedness.<ref name=Conley/>