The 71st Street bridge at Riverside was blocked off Friday afternoon.
Tulsa police tells FOX23 News this was due to a call they received around 2 p.m.
An unidentified woman found a device under the bridge.
The device turned out to be an empty pin grenade shell.
Police say the bomb squad was then called out to the location to examine the device.
No word on how the grenade ended up under the bridge and nobody has been taken into custody.
The bridge was only closed down for a short time.