Farmers have been using the weed killer glyphosate – a key ingredient of the product Roundup – at soaring levels even as glyphosate has become increasingly less effective and as health concerns and lawsuits mount.

Nationwide, the use of glyphosate on crops increased from 13.9 million pounds in 1992 to 287 million pounds in 2016, according to estimates by the U.S. Geological Survey. 

A review of the agency’s data by the Midwest Center for Investigative Reporting shows that farmers across the Midwest used an estimated 188.7 million pounds of glyphosate in 2016 – nearly 40 times more than in 1992 when they used a total of 4.6 million pounds.  The data for the year 2016 is the latest available.

Farmers in those 12 states – including Illinois, Indiana, Iowa and Nebraska – grow most of the country’s soybean and corn crops. Glyphosate is now the primary way farmers manage weeds that would otherwise reduce the amount of grain they can produce. The Midwest accounts for 65 percent of the nation’s use of glyphosate for crops, according to the Center’s analysis.