Three fire crews were dispatched to the scene of what was thought to be a gas leak in the James Street area of Cookstown last night.
It is understood, however, that the smell was gas emanating from a nearby sewer.
Two people were treated by medics at the scene, but no medical issues found.
A Northern Ireland Fire & Rescue Service spokesperson said: “NIFRS received a call at 8.55pm to a report of a smell of gas at the James Street area of Cookstown yesterday evening (Tuesday, May 24).
“Two fire appliances from Cookstown Fire Station and one Fire Appliance from Dungannon Fire Station were deployed to the scene. Firefighters wearing breathing apparatus carried out an initial gas monitor, with a reading of zero.
“It is believed that sewer gas was mistaken as a gas leak. Two people were treated at the scene but no medical issues recorded in both cases.
“Northern Ireland Fire & Rescue Service finished at the scene at 9.52pm.”