I. Introduction
The Biological Weapons Convention has an unusual distinction among arms control treaties: it was the first to prohibit an entire category of weapons of mass destruction outright, and it remains, half a century later, the only one of the three major WMD conventions with no standing mechanism to verify that States actually comply with what they signed. [1] That gap did not go unnoticed at the time. The 1925 Geneva Protocol had already banned the use of biological weapons in warfare, but said nothing about their development or possession [2], and the 1972 Convention closed that loophole by prohibiting development, production, stockpiling, and acquisition of biological agents "of types and in quantities that have no justification for prophylactic, protective or other peaceful purposes" [3] - an intent-based formula covering 189 States Parties today. [4]
What the drafters left unresolved was how anyone would know whether a State was keeping its word. Biological agents, unlike fissile material or chemical precursors, are self-replicating, dual-use by nature, and producible in facilities indistinguishable from a university laboratory or a vaccine plant. That technical reality has shaped the entire subsequent history of the Convention, and it frames the central question this article takes up: whether the international legal order governing biological threats - built from a disarmament treaty with no teeth, a parallel and only loosely connected global health security regime, and a scatter of informal export-control arrangements - is equal to a threat landscape that synthetic biology has made considerably more accessible than it was in 1972.
The article proceeds in four parts. Part II sets out the BWC's prohibition and its verification deficit. Part III traces the repeated, and repeatedly frustrated, attempts to close that deficit, from the VEREX exercise of the 1990s to the Working Group established after the 2022 Review Conference. Part IV turns to the global health security architecture - the International Health Regulations and the newly adopted WHO Pandemic Agreement - that has developed, largely on a separate track, to manage biological risk from the public-health rather than the disarmament side. Part V compares the BWC's model to the Chemical Weapons Convention's inspection-based regime and considers what convergence between the two traditions might look like.
II. The Convention Without a Watchdog
Article X of the BWC commits States Parties to facilitate the exchange of equipment, materials, and scientific information for peaceful purposes [5], but the treaty contains no counterpart institution - no inspectorate, no declaration regime, no technical secretariat - to confirm that peaceful purposes are in fact all that is happening. [6] Its enforcement clause allows a State to lodge a complaint with the U.N. Security Council, which may then authorise an investigation [7], but this route has never once produced a finding of noncompliance, in part because credible complaints tend to implicate States that can veto the Council's response. The result is a prohibition that is, in the most literal sense, unpoliced: 189 governments have promised not to build biological weapons, and no external body is positioned to check.
This is not an oversight so much as an unresolved argument. Every attempt to design a verification mechanism has run into the same objection: that microorganisms multiply, that dual-use research is everywhere, and that an inspection regime rigorous enough to catch cheating would also be intrusive enough to expose legitimate pharmaceutical and agricultural research to commercial espionage or diplomatic harassment. Whether that objection is a genuine technical constraint or a convenient excuse for States unwilling to open their laboratories to outsiders is a question the Convention's history does not answer cleanly - because both dynamics have been present at once.
III. Thirty Years of Trying: From VEREX to the Working Group
The Third Review Conference in 1991 established the Ad Hoc Group of Governmental Experts, known by its acronym VEREX, to identify potential verification measures on a purely technical basis. [8] VEREX reported back in 1993 with twenty-one candidate measures - on-site inspections, mandatory declarations of high-risk facilities, remote sensing, and others - designed to operate as a package rather than in isolation. [9] States Parties then spent six years negotiating those measures into a binding protocol, producing a lengthy composite text by 2001. [10] The negotiations collapsed that same year when the United States withdrew, arguing that the draft protocol would neither catch determined cheaters nor avoid burdening legitimate biodefence and pharmaceutical research - in short, that biological verification was close to a contradiction in terms. [11] For two decades afterward, compliance and verification were effectively off the table at BWC meetings, treated as the issue too politically radioactive to reopen.
That changed, modestly, at the Ninth Review Conference in December 2022, which established a new Working Group on the Strengthening of the Convention with a mandate spanning seven areas, compliance and verification among them. [12] The mandate's other six areas - international cooperation, science and technology review, confidence-building, national implementation, assistance and response, and institutional arrangements - were arguably easier to reach consensus on [13], and progress on verification specifically has been halting.
The Working Group's fifth session in December 2024 ended when a single State Party blocked adoption of the year's cumulative report on its final evening, undoing months of preparatory work in a matter of hours. [14] The year 2025 carried real symbolic weight - the centenary of the Geneva Protocol and the fiftieth anniversary of the BWC's entry into force - but disagreement over the Working Group's own mandate, reportedly driven by a divergent Russian interpretation of its scope, prevented States from marking the occasion with a Special Conference or any substantive breakthrough. [15]
The practical constraints are almost as telling as the political ones: by mid-2025, the Working Group had only seven days of meeting time allotted through the end of the year for the compliance-and-verification agenda item specifically - plainly not enough to design a regime that is, in the phrase used by outside observers, "politically palatable, technologically feasible and financially viable." [16] An extraordinary eighth session in February 2026 was convened simply to finish a report the seventh session, in December 2025, had left incomplete. [17] Whatever emerges from this process, it will not resemble the ambitious, inspection-heavy protocol that failed in 2001; the more realistic outcome is an incremental package of voluntary and quasi-mandatory transparency measures, considerably short of verification in the sense that arms control lawyers usually mean the term.
Two other instruments fill part of the gap the BWC itself leaves open, though neither was designed as a verification mechanism and neither operates under the Convention's authority. Security Council Resolution 1540 obliges all U.N. member States to adopt domestic controls preventing non-State actors from acquiring biological, chemical, or nuclear weapons [18], addressing the bioterrorism half of the threat spectrum that a State-to-State disarmament treaty was never built to reach. The Australia Group, an informal club of forty-three countries, coordinates export controls over sensitive biological materials and equipment on a voluntary basis, entirely outside the BWC's treaty structure. [19] Both arrangements are useful, and both illustrate the same underlying point: where the Convention itself cannot verify or enforce, States have built workarounds alongside it rather than fixing it from within.
IV. The Parallel Track: Global Health Security Law
While the BWC's compliance debate stalled, a separate and considerably more active body of international law has developed to manage biological risk from the public-health side. The International Health Regulations, revised in 2005 and amended again in 2024, require States to detect, assess, and report events of international concern and to build minimum surveillance and response capacities; the 2024 amendments entered into force on 19 September 2025. [20] Unlike the BWC, the IHR's reporting obligations are backed by a functioning early-warning apparatus at the World Health Organization, even though the Regulations, too, lack any power to compel a reluctant State to comply. [21]
The WHO Pandemic Agreement was adopted by the Seventy-Eighth World Health Assembly on 20 May 2025. Its Pathogen Access and Benefit Sharing (PABS) system remains to be settled in an annex before the Agreement can open for signature. Article 12 sets the principles, but the operational terms - including how manufacturers would share pandemic products - remain under negotiation. After the May 2026 Assembly extended the talks, WHO reported in September 2026 that Member States had advanced the text without finalising the annex. The negotiating outcome is expected for consideration by the Eightieth World Health Assembly in May 2027, or at an earlier special session. The unresolved balance between prompt pathogen sharing and equitable access to vaccines and treatments is central to the Agreement’s practical value.
The PABS negotiations sit alongside a related and equally unresolved question in a different forum: the Convention on Biological Diversity's 2024 decision to establish the Cali Fund, a cash-based benefit-sharing mechanism for commercial use of digital genetic sequence information, funded by indicative contributions of one per cent of profits or 0.1 per cent of revenue. [27] The coexistence of a cash-based CBD mechanism and an in-kind, production-based WHO mechanism covering overlapping genetic material is, at minimum, an invitation to regulatory arbitrage, and at worst a sign that global health law and biodiversity law are solving the same benefit-sharing problem twice, in different currencies, without much coordination between them. [28]
V. Comparative Reflections and the Case for Convergence
The contrast with the Chemical Weapons Convention is instructive precisely because chemical and biological weapons have historically been regulated as a pair, dating back to the 1925 Geneva Protocol's single prohibition on both.
The CWC created a standing Organisation with a professional inspectorate empowered to conduct routine and challenge inspections at declared and undeclared sites alike. [29] The BWC, by contrast, relies on annual Confidence-Building Measure declarations that are voluntary in substance, submitted by fewer than half of States Parties in a typical year, and unverified by any external body. [30] The two treaties emerged from the same diplomatic tradition and address closely related categories of weapon, yet one has genuine enforcement architecture and the other does not - a divergence usually explained by the belief that biological verification is technically harder, but which on close inspection also reflects choices, made and re-made since 2001, about how much intrusion States are willing to accept.
Meanwhile the underlying threat has moved in the wrong direction for a treaty built on the assumption that only a handful of well-resourced state programmes could produce dangerous pathogens.
Gene synthesis, genome editing, and gene-drive technologies have lowered the technical and financial barriers to recreating or modifying pathogens with pandemic potential, in ways the drafters of 1972 could not have anticipated. [31] The same dual-use character that makes verification hard also means that a growing number of legitimate research programmes - gain-of-function studies among the most debated - sit uncomfortably close to capabilities that a hostile actor could repurpose. [32] A legal order that treats disarmament and public health as separate silos, coordinated at best through informal liaison between Geneva and the WHO, is not obviously well suited to a threat that increasingly does not respect that division: an engineered pathogen released deliberately triggers exactly the same surveillance, containment, and treatment response as a naturally emerging one, whatever the BWC's Article I might say about its origin.
None of this argues for abandoning either institution in favour of the other. The BWC retains unique normative value as a categorical prohibition, and folding disarmament obligations into a health treaty would risk diluting both. The more modest and more achievable proposal is procedural: formal liaison arrangements between the BWC's Implementation Support Unit and the WHO's health-emergency apparatus, joint reporting formats that would let a single national declaration satisfy both regimes' transparency demands, and a shared roster of forensic and epidemiological expertise that either body could call on in the event of a suspicious outbreak, regardless of which treaty formally has jurisdiction over the response.
Small measures of this kind will not resolve the compliance and verification debate that has stalled since 2001, but they would at least ensure that the two halves of the international legal order dealing with biological risk are working from the same information rather than past each other.
VI. Conclusion
Fifty years after it entered into force, the Biological Weapons Convention remains what it was at the outset: a categorical prohibition resting on trust rather than verification, sustained more by the absence of a viable alternative than by confidence that the current arrangement actually works. The Working Group process launched in 2022 has kept the compliance conversation alive longer than any effort since 2001, but its own timeline and internal disagreements suggest that a verification regime, if one emerges at all, will be modest rather than comprehensive.
Parallel to this, global health law has built a more active - if also incomplete - architecture through the revised International Health Regulations and the still-unfinished Pandemic Agreement, whose Pathogen Access and Benefit Sharing annex may yet determine whether the Agreement ever takes legal effect at all. Neither track, on its own, offers a complete answer to a biosecurity landscape reshaped by synthetic biology. What the moment calls for is not a choice between disarmament law and health law, but a deliberate effort to make the two speak to each other - because the pathogen, unlike the treaty regime meant to govern it, does not care which side of that institutional divide it started on.
Endnotes
[1] Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on Their Destruction art. I, Apr. 10, 1972, 1015 U.N.T.S. 163 [hereinafter BWC].
[2] Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare, June 17, 1925, 94 L.N.T.S. 65 [hereinafter Geneva Protocol].
[3] BWC, supra note 1, art. I (prohibiting development, production, stockpiling, acquisition, and retention of biological agents and toxins "of types and in quantities that have no justification for prophylactic, protective or other peaceful purposes," together with weapons and means of delivery designed to use such agents for hostile purposes).
[4] United Nations Office for Disarmament Affairs, Biological Weapons Convention: Background, https://www.un.org/disarmament/biological-weapons (last visited 2026) (recording 189 States Parties and four signatories as of 2025).
[5] BWC, supra note 1, art. X (undertaking to facilitate the exchange of equipment, materials, and information for peaceful uses of bacteriological science).
[6] See Jonathan B. Tucker, Biological Threat Assessment: Is the Cure Worse than the Disease?, 84 Foreign Aff. 25 (2005) (describing the absence of any standing verification or inspection mechanism under the BWC).
[7] BWC, supra note 1, art. VI (permitting a State Party to lodge a complaint with the U.N. Security Council, which may then initiate an investigation) (in practice never successfully invoked, given the veto power of permanent members implicated in noncompliance disputes).
[8] Third Review Conference of the States Parties to the BWC, Final Declaration, U.N. Doc. BWC/CONF.III/23, at 17-19 (1991) (establishing the Ad Hoc Group of Governmental Experts to Identify and Examine Verification Measures, known as VEREX).
[9] VEREX, Report, U.N. Doc. BWC/CONF.III/VEREX/9, at 10-14 (1993) (identifying twenty-one potential verification measures, including on-site inspections, declarations of dual-use facilities, and remote sensing).
[10] Ad Hoc Group of the States Parties to the BWC, Composite Text, U.N. Doc. BWC/AD HOC GROUP/CRP.8 (2001) (the draft verification protocol negotiated over six years before collapsing).
[11] See Council on Strategic Risks, Derailment of the Fifth Working Group of the Biological and Toxin Weapons Convention (Jan. 16, 2025) (recounting the United States' 2001 withdrawal from the protocol negotiations on the ground that biological verification was inherently unworkable).
[12] Ninth Review Conference of the States Parties to the BWC, Final Document, U.N. Doc. BWC/CONF.IX/9, ¶ 118 (2022) (establishing a Working Group on the Strengthening of the Convention with a mandate covering seven substantive areas, including compliance and verification).
[13] Daniel Horner, Strengthening the Biological Weapons Convention, Arms Control Ass'n (Dec. 2024) (listing the Working Group's seven mandated areas: international cooperation and assistance; science and technology; confidence-building and transparency; compliance and verification; national implementation; assistance and response; and organisational, institutional, and financial arrangements).
[14] Council on Strategic Risks, supra note 11 (describing the collapse of the Fifth Working Group session in December 2024, when a single State Party blocked adoption of the session's report on its final evening).
[15] Global Biodefense, Biological Weapons Convention Working Group Addresses Verification and Biosecurity (Aug. 11, 2025) (noting that 2025 marked both the centenary of the Geneva Protocol and the fiftieth anniversary of the BWC's entry into force, and that disagreement over the Working Group's mandate - attributed to Russia's divergent interpretation - forestalled a Special Conference to mark the occasion).
[16] Matt Field, How the Biological Weapons Convention Could Verify Treaty Compliance, Bull. Atomic Scientists (Mar. 2024) (reporting that the Working Group had only seven days allotted through the end of 2025 for discussion of compliance and verification, insufficient to produce a regime that is "politically palatable, technologically feasible and financially viable").
[17] Rappresentanza Permanente d'Italia presso la Conferenza del Disarmo, The Biological Weapons Convention (2026) (recording that an extraordinary eighth session of the Working Group met in February 2026 to complete a final report left unfinished at the seventh session in December 2025).
[18] S.C. Res. 1540, ¶ 2 (Apr. 28, 2004) (obligating States to adopt and enforce domestic controls to prevent non-State actors from acquiring, developing, or trafficking in biological, chemical, and nuclear weapons and related delivery systems).
[19] Australia Group, Guidelines for Transfers of Sensitive Chemical or Biological Items (rev. 2023) (a voluntary, informal export-control arrangement among forty-three participating countries, operating outside the BWC's treaty structure).
[20] International Health Regulations (2005), World Health Assembly Res. WHA58.3 (May 23, 2005), as amended by World Health Assembly Res. WHA77.17 (June 1, 2024), entered into force Sept. 19, 2025 [hereinafter IHR (2005)].
[21] WHO, Member States Advance Vital Work in Support of WHO Pandemic Agreement (Sept. 25, 2025) (noting the entry into force of the 2024 IHR amendments on Sept. 19, 2025, alongside continuing work on the Pandemic Agreement).
[27] Pathogen sharing in the digital age: The unfinished agenda of the WHO pandemic agreement, PMC (2025) (noting that the PABS system contemplates in-kind contributions of twenty per cent of relevant production, in contrast to the cash-based Cali Fund established under the Convention on Biological Diversity).
[28] Convention on Biological Diversity, Conference of the Parties, Decision 16/2, Annex ¶¶ 3, 13 (Nov. 1, 2024) (establishing the Cali Fund for the Fair and Equitable Sharing of Benefits from the Use of Digital Sequence Information on Genetic Resources).
[29] Convention on the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on Their Destruction arts. VIII-IX, Apr. 29, 1997, 1974 U.N.T.S. 45 (establishing the Organisation for the Prohibition of Chemical Weapons and a standing inspectorate).
[30] See Filippa Lentzos, Compliance and Enforcement in the Biological Weapons Convention, in Verifying Compliance 265 (Trevor Findlay ed., 2021) (contrasting the BWC's reliance on Confidence-Building Measure declarations, which are voluntary, unverified, and submitted by fewer than half of States Parties in most years, with the mandatory, inspection-backed regime of the Chemical Weapons Convention).
[31] See Kevin M. Esvelt, Delay, Detect, Defend: Preparing for a Future in which Thousands Can Release New Pandemic Agents, Geneva Papers (2022) (arguing that advances in gene synthesis and design tools have lowered the technical barrier to recreating or engineering dangerous pathogens).
[32] National Academies of Sciences, Engineering, and Medicine, Biodefense in the Age of Synthetic Biology 1-4 (2018) (assessing the dual-use risks posed by genome editing, DNA synthesis, and gene-drive technologies).