Radon

This doesn't include the 30,000 new cases of lung cancer due to radon poisoning expected if Spectra Energy brings Fracked Gas from the Marcellus Shale Formation in Pennsylvania into NYC. 

According to a study conducted by Radioactive Waste Management:

Radon in Natural from Marcellus Shale  by Marvin Resnikoff, Ph.D.

"The number of persons potentially at risk in New York State can be roughly determined 
by the number of kitchen stoves fueled by natural gas in New York State multiplied by  
the number of persons in a household.  According to the US Department of Energy
23, the number of households with natural gas fueled stoves in New York State is 4.4 million.  
From the 2010 Census, the average number of persons per household in New York State 
is 2.69.  Thus 11.9 million persons in New York State are potentially at risk.  Multiplying 
the lifetime risk of inhaling radon gas by the number of persons in New York State at 
risk, we finally determine the potential number of lung cancers as ranging between 1183 
to 30,484, out of a population at risk of 11.9 million.  This is a major environmental 
impact and a public health impact that the New York Department of Environmental 
Conservation must carefully assess."