Alan: Jay and I sometimes disagree about data sources. I think that he is more demanding than I am. I more often rely on the ATSDR toxicological profiles than the HSDB. Here is a link for the ATSDR toxicological profile on mercury, which is a little older than most of the profiles they publish. http://www.atsdr.cdc.gov/toxprofiles/tp46.html Stay healthy, Chris Marlowe Scotch Plains, NJ 07076 908 / 754 - 5160 732 / 539 - 8128 (cell) Chrismarlowe**At_Symbol_Here**comcast.net