A massive smoke cloud rising near Milton yesterday prompted queries about the possibility of an explosion.
But the cloud proved to be from a burn off.
Fire Service spokesman Andrew Norris said firefighters from the Milton Volunteer Fire Brigade were called just before 3.30pm to a large vegetation fire inthe ''foothills'' near North Branch Rd.
The cloud of smoke was seen by people from Mosgiel to Milton.
Several contacted the Otago Daily Times asking if the smoke was the result of an explosion.
Mr Norris said the permitted fire created plenty of smoke and was ''under control'' when the firefighters arrived.
Otago Rural Fire Authority deputy principal rural fire officer Kerry O'Neill said the vegetation fire on a farm was started by squirting ''fire gel'' from a helicopter.
''It's a bit like napalm ... it comes down in little fire balls.''