Researchers at the Yale School of Public Health found that children who live close to fracking sites in Pennsylvania have a higher risk for lymphoblastic leukemia — the most common form of childhood cancer, according to State Impact Pennsylvania.

The Pennsylvania Cancer Registry and state data on unconventional oil and gas drill sites were used to determine that children born within two kilometers or 1.24 miles of an active site were two to three times more likely to be diagnosed with acute lymphoblastic leukemia from 2 to 7 years old.

The study was published earlier this month in the journal Environmental Health Perspectives. It looked at 405 children diagnosed with lymphoblastic leukemia between 2009 and 2017 and included 2,080 controls matched by birth year. The study also accounted for a variety of socioeconomic, demographic and biological factors that could have impacted the findings.

Learn more: State Impact Pennsylvania > Children living near Pa. fracking sites are at increased risk of leukemia study finds