Residents of north Wales, including campaigners Natalie Dugdale and Michael Phillips, are calling for voluntary blood testing after discovering their local communities were used as dumping grounds for PCBs, cancer-causing chemicals once produced by Monsanto. A BBC documentary revealed that Llwyneinion lagoon near Wrexham, where residents and children have spent time, alongside 13 other sites, were contaminated with these "forever chemicals" that persist in the environment. This matters because residents are concerned about long-term health effects and want to establish who has been exposed, particularly given reports of rare cancer diagnoses among former childhood visitors to the lagoon.

Public Health Wales has rejected calls for blood testing, arguing that such tests do not reliably assess individual exposure levels and could cause unnecessary concern among residents. However, Michael Phillips, who played at Llwyneinion lagoon as a child, was found through private testing to have "very high" levels of PCBs in his blood; he reports that many childhood friends have developed or died from rare cancers. The newly formed campaign group comprises hundreds of residents from villages near the former Monsanto works in Cefn Mawr, Acrefair, and Trevor, and investigators found elevated PCB levels in soil samples in publicly accessible areas beyond the lagoon's fenced perimeter.