Fearing sod producers are losing revenue to out-of-state synthetic turf companies, Turfgrass Producers International and the North Carolina Sod Producers Association sent a letter to high-ranking officials at the University of North Carolina warning of higher injury rates connected to playing on turf.

The letter was sent to UNC's Board of Governors, athletic director Bubba Cunningham and campus health executive director Ken Pittman, among others in the wake of an announcement that the university was replacing the natural grass in Kenan Memorial Stadium with synthetic turf at the request of football coach Mack Brown.

As reported by the CBS affiliate in Raleigh, the natural grass groups point to a recently released study published by the American Journal of Sports Medicine that points to an increase in injuries on artificial turf. The study looked at nearly 214,000 distinct plays during the 2012-16 NFL seasons and found the rate of knee/ankle/foot injuries resulting in any loss of playing time to be 56 percent higher on synthetic turf. Specifically, the study claims a 68 percent increase in high ankle injuries on synthetic turf resulting in time loss and a 103 percent increase in players sitting out at least eight days. 

The peer-reviewed study also says 1 in 5 concussions are from head-to-turf impacts, with the critical fall height for concussions being less than half what it is on natural grass. 

According to the letter, UNC's decision "sets a precedent by one of North Carolina’s leading educational institutions who has chosen to replace a locally-grown, successful, NC agricultural product with an out-of-state plastic product that is not only more expensive, but less safe for NC kids and athletes."

In a statement, UNC said the move was the "best option for our football team" and other varsity programs that use Kenan Stadium. Cunningham has reportedly added that the conversion decision "was not an easy one," and that it "was made only after considering numerous factors" and in the interest of the "health and well-being of our students."

Paul Steinbach is Senior Editor of Athletic Business.