Article content Carfentanil, a highly toxic opioid, is likely mixing with drugs circulating in Oxford County, health officials warned Friday on the heels of four fatal opioid overdoses in the area. Regional HIV/AIDS Connection, a regional non-profit in Southwestern Ontario that provides services, including a clean needle program, advised Southwestern public health of an increase in carfentanil being mixed with other substances and circulating in the community’s drug supply. We apologize, but this video has failed to load. Try refreshing your browser. Carfentanil possibly circulating in local drug supply: Public health Back to video Carfentanil is an opioid 100 times more toxic than fentanyl, or 10,000 times more toxic than morphine.