Well, it now appears safe to exhale. The Volt's halo remains in place as exculpatory evidence has been offered up by no less than the local fire marshal. Speaking with Green Car Reports, the Iredell County official said, "the source of ignition seems to be from outside the area of the vehicles." Phew! To add to the evidence in the Volt's favor, it's also important to note that it wasn't gutted and materials with low melting points were still intact.
Of course, there's still the matter of the fire that occurred three weeks after being crash tested by NHTSA but it looks like it is safe to assume that if your plug-in car hasn't suffered from a side-impact event, you're good to go.