By Muhammad Mamman
— The Office of the National Security Adviser (ONSA) has formally instructed Nasir el‑Rufai, former governor of Kaduna State, to submit supporting evidence to the Department of State Services (DSS) in connection with his allegations concerning the procurement of a dangerously toxic chemical by the nation’s top security office, sources familiar with the matter have told TheCable.
Mr el‑Rufai had publicly challenged reports suggesting that ONSA procured roughly 10 kilogrammes of thallium sulphate, a colourless, odourless and highly poisonous compound, allegedly sourced from a supplier in Poland. The former governor’s claims triggered widespread concern over public safety and transparency in state institutions. 
In a letter dated 30 January 2026 and addressed to the National Security Adviser, Nuhu Ribadu, Mr el‑Rufai sought clarification on the purpose, authorisation, regulatory oversight and handling of the substance — emphasising that thallium compounds are “highly toxic and tightly controlled”. 
According to media reports, the directive from ONSA requires Mr el‑Rufai to produce documentation, correspondences and any other material he has to substantiate his claims to the DSS for further investigation, marking an escalation in the dispute between the ex‑governor and the country’s security apparatus. Sources say this is intended to determine whether the allegations have basis, or whether they constitute an unfounded attack on national security institutions. 
The controversy has elicited a range of reactions across Nigeria’s political landscape, with some demanding full transparency and parliamentary scrutiny, while others urge restraint, warning that unverified claims could undermine confidence in security agencies. As of the time of writing, ONSA has neither released an official public statement addressing the alleged procurement nor responded directly to requests for comment on the DSS referral.
