In April 2008 during an online Globe chat with a BPA expert, a reader asked if the Sigg bottles were safe. Mia Davis of Clean Water Action warned readers then she didn’t know. Because aluminum has been linked to health problems, she noted, aluminum cans are sometimes coated with a BPA resin. She said she had asked Sigg but all they told her was their resin did not leach BPA.

Sigg came out last month and acknowledged that its resin had “trace amounts” of BPA in bottles made before August 2008. An Associated Press story notes the company knew about it since 2006. Davis says she is sure BPA is leaching from Sigg bottles – it leaches from everything else.