Lead Crystal

Lead Crystal is a type of glass made with lead. Vintage glassware and decanters (especially pricy/fancy ones) may be made of lead glass, so bars should ensure any vintage glassware is either not lead crystal or if it is, that it is not used to store beverages. 

According to a 1991 New York Times story [link]:

• Do not use lead crystal every day. Occasional use is all right, but if you have a daily glass of wine, don't drink it from a crystal goblet.
• Don't store foods or beverages for long periods in crystal. This is particularly true for acidic juices, vinegar and alcoholic beverages. Mr. Burke defines a week or two as long. Others say overnight is the maximum.
• Women of child-bearing age should not use crystal ware. 
• Don't feed children from crystal bottles or tumblers.”

According to the Seattle Times [link] from 2008: "Does this mean you should stop using lead-crystal decanters and stemware completely? Not necessarily, unless you want to be extremely cautious. The Nibble notes that EPA standards for lead content will not be exceeded if you serve your wine (or water) in your crystal stemware during the course of a meal. As for decanters, it’s safest to use them quickly to decant the wine off its sediment, then pour it back into the original bottle for serving."

How to Identify Leaded Glass

According to the book Hacking Whiskey: 

• Hold it up to the light. A leaded decanter will typically cause a "rainbow effect" when light is refracted through it. This isn't always the case, but if you see the rainbow, lead poisoning is a possibility. 
• If your decanter is labeled as "plain pressed glass," it is probably fine. 

Further Reading:

"Storing Wine in Crystal Decanters May Pose Lead Hazard" New York Times (1991) [link]

"F.D.A. Issues Warnings On Using Lead Crystal" (1991) [link]

"Lead Glass - Safety" Wikipedia [link]