This is why the EPA's 'secret science' proposal alarms public health experts | Opinion | PennLive.com

"Done by Harvard researchers, the 1993 Six Cities study identified fine particulate pollution that goes deeply into the lungs, largely produced from fossil fuel combustion, as being harmful to health. This core finding, along with other studies, led to new standards that saved thousands of lives.

But under the current proposal, data from that study could not be used to inform EPA policy because the underlying data was not made publicly available."