Constitutional FAQ Answer #36
Q36. "If you exercise your 5th amendment right and the court grants immunity and you still refuse to incriminate yourself you can be held in contempt and sent to jail. Locally, years ago a reputed Mafia boss pleaded the 5th to every question he was asked about the 'mob.' He was granted immunity from prosecution but continued to 'take the 5th.' His contention was that he would get immunity from prosecution by the authorities but no immunity from the 'street.' He served 7 years in NJ prison for contempt of court."
A. The Supreme Court has held, in many cases over time, that the granting of immunity removes the danger of prosecution, and that is what the 5th Amendment protects. It does not envision protection from elements outside the government as a valid reason for refusing to testify. This makes perfect sense to me, actually. Since nothing he said could land him in jail, he could be compelled to speak. The "real-world" consequences have no bearing. It is an interesting legal point.