Chemical found widely in the environment causes cancer, global experts determine
By Shannon Kelleher
A group of global scientific cancer experts this week classified a widespread chemical known as PFOA as carcinogenic to humans, confirming decades of research, and building on concerns about human and animal exposure to that chemical and to the larger class of manmade substances that are commonly known as “forever” chemicals because of their persistence in the environment. Separately, the experts deemed a related chemical called PFOS as possibly carcinogenic to humans.
The classifications, published Thursday in The Lancet Oncology, were determined by a working group of 30 experts from around the world through the International Agency for Research on Cancer (IARC), an arm of the World Health Organization (WHO). The experts convened in Lyon, France Nov. 7-14 to review published literature on the health risks of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Both are types of per-and poly fluoroalkyl substances (PFAS).
“This latest action highlights and reaffirms the concerns we have been raising for decades that these man-made ‘forever chemicals’ present a serious threat to human health, mandating that appropriate steps be taken to prevent and address exposures,” said Rob Bilott, an environmental lawyer for the Ohio-based firm Taft Law who has spent over two decades exposing the dangers of PFAS chemicals.
In classifying PFOA as carcinogenic, the IARC scientists said they found “sufficient” evidence for cancer in experimental animals exposed to PFOA and “strong” evidence that the chemical affects gene expression and immune response in humans exposed to PFOA. They also found limited evidence for cancer in humans, identifying a link to renal cell cancer and testicular cancer.
The scientists said that the research shows PFOS is “possibly” carcinogenic to humans. They said they found strong mechanistic evidence that the chemical affects gene expression and immune response in exposed humans, along with several other key characteristics of carcinogens. They also found limited evidence linking PFOS to cancer in experimental evidence but ‘inadequate evidence’ linking it to cancer in humans.
It remains to be determined how, or if, the new classifications may impact thousands of lawsuits that are pending in US courts against PFAS makers DuPont and 3M. The companies have been sued by individuals as well as by drinking water utilities and municipalities over alleged harms tied to PFAS contamination.
On Monday, a US appeals court turned back a large class action lawsuit brought on behalf of Ohio residents, finding there was not sufficient proof that the companies caused the exposure alleged in the case. Lead plaintiff Kevin Hardwick, who worked as a firefighter for 40 years and used PFAS-containing foams, brought the suit in 2018, alleging that the companies caused his blood to become contaminated with potentially dangerous levels of PFAS chemicals. Hardwick asked for a panel of scientists to study the effects of PFAS in his body and for medical monitoring.