Pregnant women living near active oil and gas wells at risk of giving birth to babies with low birth weights
Living near active oil and gas wells may put pregnant people at higher risk of having low birth weight babies, especially in rural areas, according to a new analysis of birth outcomes in California.
The study, funded by the California Air Resources Board and one of the largest of its kind, analyzed the records of nearly 3 million births to people living within 10 kilometers of at least one oil or gas well between 2006 and 2015. Unlike previous studies, it examined births in both rural and urban areas, and people living near both active and inactive oil and gas sites.
The study associates proximity to active oil and gas well sites with adverse birth outcomes and says that living near them is tied to low birth weights in infants. The research team found that in rural areas, pregnant women who lived within 1 kilometer of the highest producing wells were 40% more likely to have low birth weight babies and 20% more likely to have babies who were small for their gestational age compared to people living farther away from wells or near inactive wells only. Among term births, babies were 36 grams smaller, on average, than those of their counterparts, says the study published in Environmental Health Perspectives. Those who lived near active wells in urban areas also had slightly increased odds of having small for gestational age babies than their counterparts, said the research team. The study did not find a significant relationship between proximity to oil and gas wells and premature births. While it is unclear why the differences in birth weight were more pronounced in rural areas than in urban areas, the researchers hypothesize that other factors - such as differences in indoor air quality, maternal occupation, or housing conditions - may have impacted the results.
The findings add to a growing body of evidence linking proximity to oil and gas wells to a variety of adverse birth outcomes, including premature birth, heart defects, and low birth weight. “Being born of low birth weight or small for gestational age can affect the development of newborns and increase their risk of health problems in early childhood and even into adulthood. When you see a shift of over 30 grams of birth weight among term infants, from an individual clinical perspective, it may not seem like a lot. But when you see that kind of large population shift in birth weight, that can have significant population-level implications for infant and children's health,” said senior author of the study, Rachel Morello-Frosch, a professor of public health and environmental science, policy and management at the University of California, in the analysis.
The report says that while oil production in California has generally declined over the past three decades, and stricter regulations were issued last year on new fracking permits in the state, 24 new fracking permits were issued in early April, and another 282 are awaiting review.
According to the researchers, the study is the first to characterize the implications for “perinatal health of active oil and gas production” in California. They say the results can inform decision-making in regulatory enforcement and permitting activities. The team emphasizes that scientific evidence of adverse health effects facing vulnerable populations, including pregnant women, should be taken into account as people debate the extent to which California wants to expand oil and gas drilling in the state.
Previous research linking oil and gas production to adverse birth outcomes has examined people living near fracking sites in Colorado, Pennsylvania, Oklahoma, and Texas. Oil production in California differs from some of these other regions because the infrastructure is generally much older, and the state has a high number of inactive wells, say experts. Besides, owing to the geology of the region, many of the sites use enhancement techniques, including fracking and steam and water injection, to access oil reserves, says the report.
“Both active and inactive oil and gas sites create a myriad of environmental hazards that have the potential to impact perinatal health, including air and water pollutants, noise, and excessive lighting. However, with limited access to the production sites themselves, it can be hard for researchers to pinpoint precisely what factors might be contributing to adverse birth outcomes,” says the analysis.
The research team says that a lot of the equipment being operated on-site is a contributor to air pollution, but how much air pollution is unknown because the inventory industry reports are estimated based on emissions factors, as opposed to measured emissions levels. The experts assume that with greater production volume, the equipment is being used more intensively. “That may be a significant contributor to why we see some impacts related to adverse birth outcomes,” said the team.