The panel, inaugurated on 3 July, was also asked to investigate the reasons behind refineries' failure to commence operation despite the huge funds allocated for that purpose annually.
The Senate ad hoc committee investigating the importation of adulterated petroleum products has postponed its planned public hearing until further notice.
Chairperson of the Committee, Opeyemi Bamidele, disclosed this in a statement on Sunday.
The hearing was earlier scheduled for 10 to 12 September.
The postponement comes amid persistent circulation of dangerous fuel across the country.
Mr Bamidele, the senator representing Ekiti Central Senatorial District, explained that the hearing was postponed to enable the panel "to consult more widely with expanded stakeholders within and without the petroleum industry and legislative exigencies to deepen further due diligence in the conduct of the investigative hearing."
He also noted that the decision is in the country's interest and will allow the committee members to find a better approach to solving the challenges facing Nigeria's petroleum sector.
"While we deeply regret all inconveniences it may have caused all the stakeholders collectively or individually, this decision was taken purely and solely in the national interest," Mr Bamidele added.
The senate leader said a new date for the hearing would be announced soon.
Dangote's allegation
The management of the Dangote refinery had recently accused the Nigerian Midstream and Downstream Petroleum Regulatory Authority (NMDPRA) of indiscriminately granting licences to marketers to import dirty refined products into the country.
Depot and Petroleum Products Marketers Association of Nigeria have since denied the allegation.
Aside from damaging vehicles, the contaminated fuel is causing economic sabotage to Nigeria's petroleum industry.
Background
On 3 July, the Senate inaugurated a 15-member committee to investigate the importation of hazardous petroleum products by the Nigeria National Petroleum Corporation Limited (NNPCL).
This followed a motion by Asuquo Ekpeyong (APC, Cross River).
The committee was mandated to unravel the circumstances surrounding the persistent importation of hazardous fuel and to reveal the identity of the people behind the importation.
The panel was also asked to investigate the reasons behind refineries' failure to commence operation despite the huge funds allocated for that purpose annually.
At a press conference on 25 July, the committee promised to execute the tasks fairly in the country's interest.
On 7 August, the committee held an interactive session with individuals and companies in the petroleum industry at the National Assembly Complex, Abuja.
During the session, Mr Bamidele expressed displeasure with persistent long queues at petrol stations nationwide. He condemned the failure of government-owned refineries to function despite successive governments committing billions of dollars to their rehabilitation yearly.