Babies born downwind of a coal-fired power plant in neighboring Pennsylvania had an increased risk of being underweight, say Lehigh researchers.
Children born in four northwestern N.J. counties may have been impacted before birth by coal emissions from a power plant along the Delaware River in Pennsylvania, researchers say.
While the health dangers of coal emissions have been long documented - asthma and cardiovascular problems - they now appear to extend to pregnancy as well.
Researchers at Lehigh University reached that conclusion after combining three records: The emissions from a Pennsylvania coal-powered electricity plant, weather records on wind direction, and the birth weights of babies born in adjoining counties.
They found an 6.5 percent increase in babies born with low birth weights of 5 lbs, 8 oz. or smaller, and a 17.1 jump in those with very low birth weights of 3 lbs., 5 oz.
The impact was seen in Morris, Hunterdon, Warren and Sussex counties, in locations as far as 20 to 30 miles away from the power plant.
Lead researcher Muzhe Yang said it's the first time anyone has looked at the prenatal impact of coal emissions.
The coal-fired portions of Portland Generating Station, located in Upper Mt. Bethel Township across the river from the Warren County town of Columbia near Route 80, have been closed since May of 2013, said a spokesman for NRG Energy Inc., of Princeton.
It was closed as part of the settlement of a lawsuit brought by the states of New Jersey and Connecticut alleging noncompliance of the Federal Clean Air Act.
"Not one ounce of coal has been combusted since the consent decree went into effect," said NRG spokesman David Gaier.
However, three turbines at the plant that remain operational, and can run on either natural gas or diesel oil. They operate only rarely, Gaier said, during times of peak power demand when requested by the regional electricity grid.
The report is published today in the Journal of Policy Analysis and Management. It looked at all live, single (ie not twin or triplet) births from 1990 through 2006.
The study most likely underestimates the prenatal harm of coal emissions because it studied people who live in areas that are affluent compared to the country as a whole, Yang said.
Low birth weights are typically associated with poorer women who fail to get prenatal care or may have underlying health problems. Yet the increase in low birth weights found in the study occurred in a group of women who most like received better than average prenatal care, he said.
It's unclear if the affected babies were small because they were born prematurely, or whether they were born full-term but still small. That's because researchers only had data on birth weight, not the length of gestation.
Sulfur is known to induce "intrauterine oxidative stress," Yang said. That in turn can impede growth.
The impact was seen even though researchers didn't include pregnancies in the five zip codes closest to the plant. They theorized women in those towns likely were aware of emissions and may have taken precautions to avoid them.
The study was able to make a strong case the culprit was the Pennsylvania plant, Yang said, because they were studying a largely rural area that had no other significant source of sulfur dioxide pollution.
Yang said the study shows the impotence of state-by-state environmental regulations, because emissions can easily cross state borders to render harm.
"We want people to see that we do have a real case where cross border pollution impact is not resolved by state by state regulations," he said.
Kathleen O'Brien may be reached at kobrien@njadvancemedia.com. Follow her on Twitter @OBrienLedger. Find NJ.com on Facebook.