Good news! The NHTSA has looked into it and found that there is no defect as regards the battery of the Volt catching fire and that the repairs that GM has instituted will resolve the problem; the one that does not exist.
“The agency’s investigation has concluded that no discernible defect trend exists and that the vehicle modifications recently developed by General Motors reduce the potential for battery intrusion resulting from side impacts,” NHTSA said in a statement.
I guess this is the type of gibberish that one might expects when the regulator of an industry is a 25% shareholder.