They were found dead along the Baban Gwari roundabout on the Katsina road of the Kano metropolis.
The Kano State Fire Service on Sunday said it found the bodies of two in a diesel reservoir.
The spokesperson of the fire service in Kano, Saminu Abdullahi identified the deceased persons as Philip Osando, 40, and Philip Emmanuel, 35.
Mr Abdullahi said they were found dead along the Baban Gwari roundabout on the Katsina road of Kano metropolis.
He said they were trapped and suffocated inside the diesel reservoir tank while making an effort to refill it.
"On Saturday 28 October 2023, received an emergency call at about 20:20 hrs from one Inspector Abubakar Surajo reporting an incident at Katsina Road By Baban Gwari Roundabout.
"When our men reached the area at about 20:27 they found two men Philip Osando about 40 years old and Philip Emmanuel about 35 years old, who were working with Roadside Digital Advertising Display Board company at Katsina Road.
"They were informed to prepare for receiving diesel, and in that process, they entered the diesel reservoir to clear the tank, thereafter they were suffocated inside, when the truck driver arrived he tried to gate one of them by phone but there was no response.
"There and then when checking the area they found them inside the diesel tank, victims were rescued unconscious and later confirmed dead. The victim was handed over to Inspector Abubakar Surajo of the Dala police division.
" The cause of the incident is under investigation.
"Safety is for everyone to think before action, doubles check is very important," Mr Abdullahi said.