Poisoning the Forest for the Trees

This episode of Reveal investigates the widespread use of glyphosate, the active ingredient in Roundup, across California's forests—particularly in the aftermath of devastating megafires like the Dixie and Park Fires. Reporter Nate Halverson uncovers how the U.S. Forest Service and private timber companies, including Sierra Pacific Industries, are spraying glyphosate on over 10,000 acres of public and private land to promote the growth of young trees by eliminating competing vegetation. Despite growing scientific evidence linking glyphosate to cancer and other health issues—backed by the WHO classifying it as a probable carcinogen—regulators continue to rely on a discredited 2000 scientific paper, the Williams et al. study, which was later retracted due to evidence of ghostwriting by Monsanto employees. The episode reveals how Monsanto orchestrated a decades-long campaign to manipulate scientific consensus, funding and shaping studies to falsely assert glyphosate's safety. This manipulation has had lasting consequences, influencing federal policy and enabling continued spraying in ecologically sensitive areas like Yosemite, Lake Tahoe, and Lassen National Forest. The story culminates in a broader critique of corporate influence on science and regulation, with Harvard professor Naomi Oreskes exposing how the same tactics used by the tobacco industry are now being deployed to protect toxic chemicals. The episode raises urgent questions about environmental justice, public health, and the integrity of scientific research in the face of powerful corporate interests. The episode also highlights personal stories from residents like Joe Van Meter, whose family-run resort in Northern California is surrounded by sprayed forest land, and who fears for his children’s health and the purity of their water supply. Despite the Forest Service’s claim that glyphosate use is safe when applied according to label instructions, evidence from worker exposure, contaminated water sources, and the retraction of a foundational study undermines that assurance. As the Supreme Court prepares to rule on whether victims can continue suing Roundup’s manufacturer, and as the federal government considers expanding glyphosate use under a controversial executive order, the episode argues that the real danger isn’t just the chemical—it’s the poisoned well of scientific trust that has allowed it to persist for decades.