For years, researchers have warned that chemical pollutants tied to fossil fuels have become so pervasive that they would be impossible for anyone to avoid.

A study released earlier this week may be the first indication of how widely some chemicals have spread. Researchers found multiple classes of potentially harmful chemicals where they’ve never been measured before: in the bodies of pregnant women.

Those findings have helped spur a call for policymakers to act now to protect environmental and public health from threats posed by the close connection between climate change and synthetic chemicals, most of which are derived from petroleum.

Scientists have known for decades that babies can be exposed to industrial chemicals even before birth because these chemicals can cross the placenta.

“To a disturbing extent, babies are born ‘pre-polluted,’” scientists with the U.S. National Cancer Institute reported in 2010.

The new peer-reviewed study, published Tuesday in Environmental, Science & Technology, found many chemicals that have never been measured before in pregnant women.