Environment | Daily Report

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Spina bifida and other neural tube defects are more common in babies whose mothers live in neighborhoods with high air levels of benzene – a chemical released from oil and gasoline refineries as well as traffic exhaust.

That finding was reported this week by scientists who analyzed data from the Texas Birth Defects Registry and compared it to federal models of air pollutants.

“This study provides the first assessment of the relationship between maternal exposure to ambient levels of BTEX (benzene) and the prevalence of neural tube defects in offspring,” the scientists wrote. “Our analyses suggest that maternal exposure to ambient levels of benzene is associated with the prevalence of spina bifida among offspring.”

California is home to 13 oil refineries.

California Energy Commission

Neural tube defects occur when the brain and spinal chord do not develop properly. These kinds of defects are relatively common, and scientists think they occur during the first four weeks of fetal development. 

Children born with these defects often suffer from both short-term and long-term health effects. Many die before they are born.

Taking folic acid before and during pregnancy has been shown to prevent neural tube defects. But the reason they appear in the first place has eluded scientists and health officials.

The authors did not investigate folic acid intake in this study. They also compared 1999 benzene levels to birth defect data gathered between 1999 and 2004. It is possible that benzene emissions fluctuated during that five-year period.

According to the Environmental Protection Agency’s 2009 Toxic Release Inventory, the biggest emitters of benzene in the state are Valero’s refinery in Benicia, Tesoro’s refinery in Martinez and Exxon Mobil Corp’s refinery in Torrance.

Here are some fact sheets from the state about the neural tube defects anencephaly and spina bifida.