Expert says more research needed

Dr. Volz, speaking to a seminar audience of about 300 at Pitt's Graduate School of Public Health in Oakland on Friday, said emissions of a variety of hazardous air and water contaminants from well wastewater ponds -- including benzene, toluene and xylene -- is clearly a cause for public health concern, especially as the number of deep wells multiply in the coming years.

http://www.post-gazette.com/pg/10240/1083398-454.stm#ixzz0yEAhqpqQ