Federal investigators are taking a new look at concerns that a herbicide found in Indiana’s drinking water could be linked to birth defects, especially in babies conceived in the summer months.

The Environmental Protection Agency limits how much atrazine, a popular weed killer often used on corn crops, can be in drinking water, and many water companies treat to lower the levels, 6News’ Joanna Massee reported.

Atrazine was effectively banned in Europe a few years ago. Within the last 90 days, the EPA began taking another look at its position on the weed killer. Quantcast

A study by biologists at the University of California, Berkeley, found that exposure to atrazine turned some male frogs into fully functioning females.

Some Indiana scientists are now questioning whether the government’s acceptable levels of the chemical are truly safe, especially for expectant mothers.

“We found that women who conceive their babies in the months between April and July, June, are the most likely to have birth defects,” said Dr. Paul Winchester, a neonatologist with St. Francis Hospital and the Indiana University School of Medicine.

Dubbed the June Effect, Winchester said research shows that the rate of birth defects correlates with spikes of atrazine in the drinking water during the summer growing season.