The Office of the National Security Adviser (ONSA) has directed former Kaduna State governor, Nasir El-Rufai, to provide evidence supporting his allegation that the agency procured thallium sulphate, a highly toxic chemical.
ONSA, in a formal response, denied the claim and requested that any supporting proof be submitted to the Department of State Services (DSS) for investigation.
Thallium sulphate is a colourless, odourless and extremely poisonous compound capable of causing death in small doses.
ONSA denies procurement claim
In a letter dated January 30, 2026, El-Rufai had written to the National Security Adviser, Nuhu Ribadu, stating that the substance was allegedly sourced from a supplier in Poland.
Responding on February 13, 2026, Brigadier-General OM Adesuyi, on behalf of the NSA, stated that ONSA neither procured nor initiated any process to purchase the chemical.
The response added that the allegation has been formally referred to the DSS for a comprehensive investigation and urged El-Rufai and any other parties with relevant information to cooperate with the probe.
“ONSA has neither procured nor initiated any process for the purchase of such material… the allegation has been formally referred to the Department of State Services for a comprehensive investigation,” the letter stated.
A copy of the response sent to El-Rufai’s Abuja residence was initially rejected by security operatives on duty, who reportedly said the head of security was unavailable. The letter was eventually delivered on Sunday and received by the head of security on his behalf.
Background
The development follows heightened tensions between El-Rufai and security authorities after he alleged access to intercepted telephone conversations involving the NSA.
The DSS is expected to invite relevant parties as part of efforts to establish the facts and ensure due diligence.
