A young man who was initially denied a crucial double-lung transplant after he tested positive for marijuana has died after undergoing the procedure in Philadelphia.

20-year-old Riley Hancey died Saturday due to complications from the transplant procedure.

"We are extremely thankful to all the wonderful doctors and staff at the University of Pennsylvania and the University of Utah for their expertise and care that Riley received," the Hancey family said in a statement, according to the PhillyVoice. "We would also like to thank the donor family, who in their own grief chose to save a life. We will never forget your kindness and generosity."

According to reports, Hancey contracted a rare form of pneumonia and developed a lung infection just after Thanksgiving in 2016. When it became clear that he would need a lung transplant in order to survive, doctors at the University of Utah reportedly rejected Hancey as a transplant candidate because he tested positive for THC, a chemical found in marijuana.

Hancey’s father claims that his son had smoked pot with his friends on Thanksgiving night in 2016 — the first time he had used drugs in a year.

Hancey’s family contacted hospitals across the country, searching for a doctor that would perform the procedure despite his drug test. University of Pennsylvania Hospital agreed to perform the procedure, and he was life-flighted to Philadelphia in February. He received his new lungs on March 28.

"We know that in our hearts we gave him every opportunity to survive," the Hancey family’s statement said. "He will live in our hearts forever. Riley is now free to climb every mountain, ski the back country, go fishing, and run every river. He will continue to do so with his family in spirit."

Drug use in transplant candidates is currently handled on a case-by-case basis, but Hancey’s case has sparked a call for a consistent policy in regard to marijuana. The drug is now legal in some capacity in 26 states and the District of Columbia.

Alex Hider is a writer for the E.W. Scripps National Desk. Follow him on Twitter @alexhider.