Meanwhile, the researchers said their findings on preterm births and birth weights among families living closer to gas wells echoed the mixed conclusions in similar studies. There were hints that gas production might reduce birth weights by less than an ounce on average.
Edward Ketyer is a retired pediatrician who sat on an advisory board for the study. He has said he expected that the studies would be consistent with previous research showing the “closer you live to fracking activity, the increased risk you have a being sick with a variety of illnesses.”
“The biggest question is why is anybody surprised about that?” said Ketyer, who is president of the Physicians for Social Responsibility Pennsylvania.
The reports were released at the start of a Tuesday evening public meeting to discuss the findings, hosted by University of Pittsburgh School of Public Health and the state Department of Health, on the campus of state-owned Pennsylvania Western University.
A number of states have strengthened their laws around fracking and waste disposal over the past decade. However, researchers have repeatedly said that regulatory shortcomings leave an incomplete picture of the amount of toxic substances the industry emits into the air, injects into the ground or produces as waste.
The Pennsylvania-funded study comes on the heels of other studies that found higher rates of cancer, asthma, low birth weights and other afflictions among people who live near drilling fields around the country.
The gas industry has maintained that fracking is safe and industry groups in Pennsylvania supported Wolf’s initiative to get to the bottom of the pediatric cancer cases. The study’s findings are emerging under new Gov. Josh Shapiro, also a Democrat, who succeeded Wolf in January.
The advent of high-volume hydraulic fracturing combined with horizontal drilling miles deep in the ground over the past two decades transformed the United States into a worldwide oil and gas superpower.
But it also brought a torrent of complaints about water and air pollution, and diseases and ailments, as it encroached on exurbs and suburbs in states like Texas, Colorado and Pennsylvania.
Establishing the cause of health problems is challenging.
It can be difficult or impossible for researchers to determine exactly how much exposure people had to pollutants in air or water, and scientists often cannot rule out other contributing factors.
Because of that, environmental health researchers try to gather enough data to gauge risk and draw conclusions.
“The idea is we’re collecting evidence in some kind of a systematic way, and we’re looking at that evidence and judging whether causation is a reasonable interpretation to make,” said David Ozonoff, a retired environmental health professor who chaired the Department of Environmental Health at Boston University.