Police blocked off part of McDowell Street Wednesday after an underground explosion caused by an electrical problem went off near its intersection with Martin Street at about 2 p.m. Duke Energy workers were working on a project in the area when a loud noise went off underneath the manhole at the intersection, followed by a thick cloud of smoke. No injuries were reported. A spokeswoman for Duke Energy told the News & Observer that there were signs of an electrical fire underground, but it is still unclear what specifically caused the explosion. The intersection will remain blocked off until the area is fully repaired.