Back in 1974, the agricultural multinational Monsanto developed a class of herbicides using glyphosate as the key ingredient. By the 1990s, the company had created corn, soy and cotton seeds genetically altered to resist glyphosate herbicides, meaning farmers could kill weeds without fearing for the health of their crops. Today, Monsanto’s Roundup is the most widely used  weed-killer in the world.
One problem: we now know with certainty that glyphosate is carcinogenic to humans and animals. Though Roundup has been plagued  by controversy for years, a report released this March by scientists affiliated with the World Health Organization definitively linked  the herbicide to increased risks for non-Hodgkin lymphoma, as well as DNA and chromosomal damage in mammals.
Roundup is only one of tens of thousands of chemicals we encounter every day in our food, clothing, furniture, electronics and cosmetics. Over 84,000 chemicals  are used in U.S. commerce, according to the Environmental Protection Agency, most of which have never been tested  for potentially toxic effects on human and wildlife health and the environment. The Human Experiment , a new documentary narrated by Sean Penn and directed by journalists Dana Nachman and Don Hardy, takes a wide-angle view on the health risks perpetuated by the chemical industry, and demonstrates how in their eyes we’re all just guinea pigs available for testing.
The documentary uses three case studies to provide a sampling of the potential health consequences of sustained chemical exposure. Marika Holmgren is an active, non-smoking Bay Area woman with no family history of cancer who receives a diagnosis of advanced breast cancer at age 37; Jenn Canvasser is a healthy young woman who discovers she has polycystic ovarian syndrome and endures several difficult, expensive rounds of IVF treatments as she and her husband try to conceive; and Hannah Cary, whose brother is severely autistic, is an advocate at the Autism Society of America. The subjects and filmmakers make the case that chemicals in the environment are responsible for these health conditions, and there is plenty of unnerving science to back up their fears.
Many of the professors and scientists interviewed in the film point to rising rates of cancer, learning disorders and infertility that cannot be fully explained by genetic drift  or changes in diagnostic criteria . Breast cancer rates have gone up more than 30 percent in both men and women since 1975. Rates of asthma have increased by 80 percent in the last 45 years, and ADHD has increased by 53 percent. As Sean Penn narrates, these conditions “are all on the rise since the dawn of the chemical revolution.”