In May 2003, an Iranian exile group accused Iran of having a biological weapons program at Lavizan. Iran has denied pursuing any such activities there.
http://story.news.yahoo.com/news?tmpl=story&cid=574&ncid=721&e=4&u=/nm/20040629/wl_nm/nuclear_iran_dc
ElBaradei said he believed a nuclear monitoring device used to detect radiation contamination in humans, spotted at Lavizan, in all likelihood came from the United States, confirming what diplomats told Reuters last week.

This confirmation could prove embarrassing to Washington, which has called on countries to crack down on exports of seemingly innocent machinery that could be used in weapons programs.