When an alleged chemical weapons incident is investigated, scientific evidence plays a critical role in helping establish what happened. Identifying the chemical involved is only one part of the picture. A sample can also provide important clues about how a substance was produced, whether it is linked to other samples, and what those findings may reveal about an incident. Chemical forensics provides the scientific tools that help answer these questions.
Recognising the growing importance of this field, the Organisation for the Prohibition of Chemical Weapons (OPCW) has released a new report examining how developments in chemical forensics can strengthen the scientific basis that supports investigations and implementation of the Chemical Weapons Convention (CWC).
The report of the Scientific Advisory Board's (SAB's) Temporary Working Group (TWG) on Chemical Forensics was presented during an event held on the sidelines of the 112th Session of the Executive Council. It sets out recommendations to help the OPCW further develop chemical forensics capabilities in support of its investigative work.
Most people are familiar with forensic science from crime scenes - the analysis of fingerprints, DNA, or trace materials to piece together what happened and who was responsible. Chemical forensics is a specialised scientific discipline that applies the same principles to chemicals and related materials.
Participants engage in an interactive chemical forensics exercise during a meeting of the Scientific Advisory Board's (SAB) Temporary Working Group (TWG) on Chemical Forensics, held on the sidelines of the 112th Session of the OPCW Executive Council (EC-112) at OPCW Headquarters in The Hague.
Strengthening the evidentiary basis for investigations
Advances in analytical chemistry, chemometrics1, data science, and artificial intelligence (AI) are expanding what chemical analysis can reveal. At the same time, chemical forensics relating to chemical warfare agents remains a challenging field. Investigations are rare, opportunities to validate forensic methods are limited, and much of the relevant data is sensitive or dispersed across different organisations.
For chemical forensics, the strength of scientific conclusions depends not only on sophisticated analytical techniques, but also on access to high-quality reference data, validated methods, and the ability to compare findings across laboratories and investigations. Building these foundations is essential to improving the evidentiary basis for investigations under the Convention.
1Using mathematical, statistical, and logic methods to extract information from chemical data.
A participant handles mock samples during a hands-on chemical forensics exercises at a meeting of the Scientific Advisory Board's (SAB) Temporary Working Group (TWG) on Chemical Forensics
A dedicated database for chemical forensics
One of the report's central recommendations is the development of a dedicated chemical forensics database to strengthen the evidentiary base available during investigations.
While the OPCW Central Analytical Database supports the identification of chemicals for verification purposes, the report concludes that investigative applications require a dedicated platform designed specifically for chemical forensics.
The proposed platform would bring together two complementary resources: a spectral databases module containing analytical reference data, and a knowledge hub containing information on chemical impurity profiles, synthetic routes, literature references, and other relevant information. Together, these resources could help investigators and laboratories compare samples, identify possible production routes, establish links between batches or incidents, and better understand the origin of chemicals.
The proposed platform would become the scientific foundation for future chemical forensic investigations, enabling data with known provenance to be collected, curated, validated, and shared in ways that support increasingly sophisticated forensic analysis.
The report also highlights the growing potential of AI and machine learning to support chemical forensic analysis, including classifying samples, identifying possible production pathways, and recognising patterns within complex datasets. As with all forensic methods, however, the report emphasises that these technologies depend on high-quality data, rigorous scientific validation, and expert interpretation.
Participants collaborate in a hands-on chemical forensics exercise during a meeting of the SAB Temporary Working Group on Chemical Forensics at OPCW Headquarters in The Hague.
Supporting the Convention through science
The work of the TWG on Chemical Forensics brought together expertise from across the SAB, the OPCW Technical Secretariat, the network of designated laboratories, and invited specialists in forensic science, analytical chemistry, AI, machine learning, and related disciplines. The Group also drew on lessons learned from past and ongoing investigations, existing verification activities, and operational experience from contingency operations in the Syrian Arab Republic.
Taken together, the report's recommendations are intended to strengthen the scientific foundations of chemical weapons investigations. By improving access to data, encouraging collaboration across the scientific community, validating forensic methods, and embracing new analytical approaches, the OPCW continues to build the scientific capabilities needed to support investigations and implement the CWC with confidence in an evolving scientific and security environment.
Background
The SAB is an OPCW subsidiary body that enables the Director-General to render specialised advice in science and technology to the Conference, Executive Council, or States Parties to the Convention.
As the implementing body for the Chemical Weapons Convention, the OPCW, with its 193 Member States, oversees the global endeavour to permanently eliminate chemical weapons. Since the Convention's entry into force in 1997, it is the most successful disarmament treaty eliminating an entire class of weapons of mass destruction.
In 2023, the OPCW verified that all chemical weapons stockpiles declared by the 193 States Parties to the Chemical Weapons Convention since 1997 - totalling 72,304 metric tonnes of chemical agents - have been irreversibly destroyed under the OPCW's strict verification regime.
For its extensive efforts in eliminating chemical weapons, the OPCW received the 2013 Nobel Peace Prize.
