As the U.S. Environmental Protection Agency prepared to make label changes for the herbicide dicamba after it caused widespread crop damage, the agency depended on the herbicide's maker for guidance, documents produced in a federal lawsuit show.

A review of more than 800 pages of documents from a lawsuit filed against the U.S. EPA in January 2017 highlights the process behind how the agency made the label changes.

The lawsuit was filed by the Center for Food Safety, the Center for Biological Diversity, the National Family Farm Coalition and the Pesticide Action Network North America in the U.S...