The Office of the National Security Adviser (ONSA) has dismissed allegations by former Kaduna State governor, Nasir El-Rufai, that it procured a highly toxic chemical, insisting that no such transaction ever took place.

In a formal response, ONSA said it had referred the allegation to the Department of State Services (DSS) for a comprehensive investigation and urged El-Rufai to submit any evidence in his possession to security authorities.

El-Rufai had earlier written to the National Security Adviser, Nuhu Ribadu, requesting clarification over claims that ONSA imported about 10 kilograms of thallium sulphate from Poland. He noted that thallium salts are extremely toxic and tightly regulated, raising concerns over public safety and institutional accountability.

In his letter, the former governor sought explanations on the purpose of the alleged importation, the identity of the supplier, regulatory approvals, storage and security arrangements, and coordination with health and environmental agencies. He said the inquiry was made in good faith to ensure transparency and protect public trust.

However, in a reply published on Sunday night by TheCable, ONSA categorically denied the claim. The response, signed by Brigadier-General O.M. Adesuyi on behalf of the NSA, stated that the office neither procured nor initiated any process to acquire thallium sulphate and had no intention of doing so.

The letter added that, given the seriousness of the allegation, the matter had been formally referred to the DSS for investigation. It noted that El-Rufai and any other individuals with relevant information would be invited to assist the inquiry by providing evidence.

“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 establishing the facts and ensuring due diligence,” the letter said.

As of the time of filing this report, El-Rufai had not publicly reacted to ONSA’s response. According to TheCable, the letter, which was initially rejected, was eventually delivered on Sunday and received by a security aide on behalf of the former governor.