The Office of the National Security Adviser (ONSA) has denied purchasing or importing Thallium Sulphate and asked former governor of Kaduna State, Malam Nasir El-Rufa who made the allegation to provide any proof to the Directorate of State Service (DSS) for a thorough investigation.
The letter was in response to el-Rufai who accused Ribadu of purchasing and importing the substance into the country.
Brigadier-General OM Adesuyi, who wrote the letter on behalf of Ribadu, said, “I have the honour to present the compliments of the National Security Adviser and to acknowledge receipt of Your Excellency’s correspondence received on 11 February 2026 requesting clarification regarding the alleged procurement of approximately 10 kilograms of Thallium Sulphate by the Office of the National Security Adviser (ONSA).
“The correspondence further indicated that information concerning the purported procurement is reportedly available to the political opposition leadership.
“In this regard, I am directed to respectfully convey that ONSA has neither procured nor initiated any process for the purchase of such material, and has no intention of doing so.
“However, I am further directed to state that the allegation has been formally referred to the Department of State Services for a comprehensive investigation.
“Your Excellency and other parties involved, who may possess relevant information relating to this claim will be duly invited by the Service to provide any evidence that may assist in an in-depth investigation, establishing the facts and ensuring due diligence.
“Please accept the assurances of the esteemed regards of the National Security Adviser.”
El-Rufai was yet to publicly respond to the matter but the online news said the letter, which was initially rejected, was eventually delivered on Sunday.
A security aide of the former governor was said to have received it on his behalf.
El-Rufai had earlier sought clarification over the alleged importation of the toxic substance from Poland, saying the was approximately 10 kilogrammes of Thallium Sulphate imported by the ONSA.
He said Thallium Sulphate was a controlled substance,” I believe it is important for public safety, democratic accountability and for maintaining public trust to confirm the intended purpose and end-use of the imported thallium sulphate; the supplier identity and whether the material was imported under an existing chemical or defence permit, and the total quantity and specific form or concentration being procured or already procured.
The former governor also demand the NSA to explain “The storage and security arrangements for the material upon arrival; The regulatory oversight and coordination in place with NAFDAC, NCDC, and relevant public-health and environmental agencies; and whether any public-health risk assessments or hazard-mitigation plans have been developed, given the compound’s extreme toxicity.”
The letter also said “I want to stress that this inquiry is made in good faith, solely to ensure that due processes, safety standards, and transparency are observed. Public confidence in the integrity of national institutions is strengthened when potential risks are openly addressed and managed.”
