The Chemical Weapons Convention prohibits the development, production, acquisition, stockpiling, retention, transfer or use of chemical weapons by Member States. Verification of compliance and investigations into allegations of use require accurate detection of chemical warfare agents (CWAs) and their degradation products. Detection of CWAs such as organophosphorus nerve agents in the environment relies mainly upon the analysis of soil. We now present a method for the detection of the nerve agent VX and its hydrolysis products by gas chromatography and liquid chromatography mass spectrometry of ethanol extracts of contaminated white mustard plants ( Sinapis alba ) which retained the compounds of interest for up to 45 days. VX is hydrolysed by the plants to ethyl methylphosphonic acid and then to methylphosphonic acid. The utility of white mustard as a nerve agent detector and remediator of nerve agent-polluted sites is discussed. The work described will help deter the employment of VX in conflict.