Opponents also contend that PREPA may contribute to the potential for abuse of discretion by the current George W. Bush Administration, which is generally perceived as friendly to the drug industry. In particular, critics are concerned about the possibility that state laws banning thimerosal containing vaccines (TCVs) may be preempted. If the HHS secretary designates that a vaccine is a covered countermeasure, thimerosal (a mercury containing preservative) can be used in the vaccine, even in states that have enacted such bans.