The U.S. National Poison Data System has published its 2010 annual report on poisonings.
There are 60 billion doses of vitamin and mineral supplements taken per year in the USA, with zero fatalities reported.
Of all reports made to Poison Control, those that involved vitamins or minerals caused zero deaths (and very few incidents).
There were no reported deaths related to multiple vitamins, any of the B vitamins, vitamins A, C, D, or E; or any other vitamin.
There was a small number of incidents listed under minerals. These mainly related to iron (not supplement pills) and sodium.
Source: Bronstein AC, Spyker DA, Cantilena LR Jr, Green JL, Rumack BH, Dart RC. 2010 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 28th Annual Report.
Minerals, page 131 of report (pdf page 163)
Vitamins, pages 137-139 (pdf 169-171)
(203 page pdf report: http://www.aapcc.org/dnn/Portals/0/2010%20NPDS%20Annual%20Report.pdf )