The 2012 stats haven't been released by the AAPCC yet (those would be in the 2013 report, due out 3rd quarter of 2014). But we have the stats for 2011 (listed in the annual report for 2012.)
Annual Reports
There were 107 cases treated in a health care facility for the category "Electronic Cigarettes:
device and/or Cartridge Containing Nicotine" and 5 for the category "Electronic Cigarettes: Nicotine Liquid." So that's 5,000 to 112.
The single fatality (in the first category) was from a 28 year old male who committed suicide by injecting himself with nicotine liquid. I imagine injecting oneself with pool chemicals would cause death, as well.