PHILADELPHIA - Plaintiffs in 192 federal multidistrict litigation asbestos cases may not rely on some 15,000 potential work site witnesses unless they can show that the witnesses were properly disclosed elsewhere during discovery, a federal magistrate judge in Pennsylvania held Dec. 27 (In re: Asbestos Products Liability Litigation [No. VI] Doyle v. A.C. and S. Inc., No. MDL 875, 08-89845, E.D. Pa.; 2012 U.S. Dist. LEXIS 183067).