http://www.handcut.com/mall/faq.asp#Question7

Can the lead in lead crystal harm you?

Lead crystal will not harm your food or drink (or you). The only way that the lead in crystal can affect its contents is if you are storing alcohol in lead crystal decanters for an extended period of time. Although there have not been a large number of health issues relating to the lead in crystal, companies and manufacturers do recommend that you only keep alcohol in lead crystal decanters for up to 3 months.

What is the difference between glass and lead crystal?

Glass is an organic substance consisting of a mixture of silicates, barates or phosphates that cools to a rigid condition without crystallization. (It can be made of quartz-sand, lime, soda, potash and lead oxide.) Crystal falls into the 3 main categories. Fine Crystal or Crystalline is made from a glass mixture that contains 6% - 10% lead oxide. Lead Crystal is made from a glass mixture that contains 10% - 24% lead oxide and Full Lead Crystal is made from a glass mixture that contains 24% lead oxide or more. For the most part, crystal by European standards regards 24% lead bearing glass as crystal. However, by American standards, any glass that is perfectly clear is considered crystal regardless of the lead content. Lead oxide in crystal gives the product clarity and sparkle. Any crystal that is hand-cut usually must be 24% lead oxide or over - otherwise the crystal would be too brittle and would break when cut or engraved.