The Office of the National Security Adviser (ONSA) has asked former Kaduna State Governor Nasir Ahmad El‑Rufai to submit any evidence he has to the Department of State Services (DSS) regarding his allegation that the office procured a highly toxic chemical, the agency said in a statement on Friday.
The directive follows a petition addressed to the National Security Adviser, Nuhu Ribadu, in which El‑Rufai said information available to political opposition leadership suggested the Office of the National Security Adviser had sourced about 10 kilograms of thallium sulphate from a supplier in Poland.
In a response letter dated February 13, 2026, signed by Brigadier‑General O.M. Adesuyi on behalf of Ribadu, ONSA said it had no involvement in procuring thallium sulphate and denied the allegation.
The letter said: “ONSA has neither procured nor initiated any process for the purchase of such material and has no intention of doing so.”
The letter further stated that the allegation has been formally referred to the Department of State Services for a comprehensive investigation.
It added that El‑Rufai and other parties in possession of relevant information would be contacted by the security service to provide any evidence that may assist in the inquiry.
The statement confirmed that prior attempts to deliver the letter to El‑Rufai’s Abuja residence were initially unsuccessful because security personnel on duty declined to accept it. The letter was later successfully delivered on Sunday and signed for on his behalf.
El‑Rufai’s allegation was made in a petition to Ribadu in which he said reports indicated that thallium sulphate, a highly toxic, colourless and odourless substance capable of causing death in small quantities, was allegedly sourced by ONSA from an overseas supplier.
He sought clarification on the purpose, supplier identity, authorisation process, quantity and regulatory oversight of the reported importation.
In response to the allegation, ONSA has denied that any such procurement took place and has reiterated that the matter is now under the DSS’s remit for further investigation.
