Union Street was closed in Plymouth in the early hours of Sunday morning following the discovery of a leaking gas pipe in a nightclub.
Police evacuated a number of local premises and the street was closed to vehicles and pedestrians while gas engineers investigated.
The cause was attributed to a leaking pipe within the disused Millennium nightclub in Union Street.
Ambulance, fire fighters and council officials were also in attendance.
A Devon and Cornwall Police spokesman said the pipe may have been leaking for some time.
The street was reopened a short time later and further investigations were continuing by gas engineers.