There are product recalls and there are major product recalls, and this one by Nokia is in the latter category as the company admits 14 million products are affected. The chargers affected are AC -3U, AC-3E and AC-4U. According to Nokia:

Nokia has announced an exchange program for a limited number of Nokia-branded chargers manufactured by a third-party supplier. We have determined that the plastic covers of the affected chargers could come loose and separate, exposing the charger’s internal components and potentially posing an electric shock hazard if certain internal components are touched while the charger is plugged into a live socket.

If you purchased your 3U or 3E before June 2009, or your 4U before April 2009, then your charger is not subject to the recall.