From the FDA's own website

[Guest guest]

This is on the FDA's website as we speak. But CDC has no preference

for vaccines with or without mercury? What planet are we on?

Thus, while enactment of FDAMA 1997 provided an official mechanism for

review of this issue, the use of thimerosal as a preservative in

vaccines had already begun to be considered by the FDA. During the

past ten years, the FDA has provided informal and formal advice to

manufacturers recommending that new vaccines under development be

formulated without thimerosal as a preservative.

http://www.fda.gov/cber/vaccine/thimfaq.htm#q5