I don't know how these things get started. As always, consider the sources quoted. Most of what I see are fear-mongering posts to other message boards referencing yet other message boards, etc. with very little/no credible supporting documentation. I find no studies that back up the claim.

In a review of literature (which can also be found on PubMed) I find exactly the opposite:

Mercury Toxicity and Antioxidants:
Part I: Role of Glutathione and alpha-Lipoic
Acid in the Treatment of Mercury Toxicity
(See page 7/16 of the pdf)

They're using ALA to remove mercury from the brain (which is part of the CNS) and other organs.

Even in some of the questionable sites, when I read far enough, they are talking about amounts of ALA much higher than those we are using here.

Doc