<<Disclaimer: Verify this information before applying it to your situation.>>

Everyone that responded said baking soda is safe.  Arm and Hammer is the soda
of choice and the only brand recommended.  However, one person did suggest
that you can make your own baking soda.

"HI, just make your own, then it is safe. One part bi carb, two parts cream
of tartar and two parts arrowroot. Sift together three times. I make about a
cup full at a time, keep in an airtight jar. Cheap too."

Thanks to all who responded!

Michael
USA, Michigan