No oil was visible in the gauge on the right engine’s oil reservoir after a February Delta Air Lines flight filled with smoke during takeoff at Atlanta’s Hartsfield Jackson International Airport, a preliminary report from the National Transportation Safety Board said Wednesday.

The National Transportation Safety Board released the preliminary report for a Delta Air Lines flight from Atlanta to Charleston that had to be evacuated after smoke filled the cabin.

Delta Flight 876 was forced to return to Atlanta and undergo emergency evacuation after smoke filled the cabin and cockpit shortly after takeoff; two passengers suffered minor injuries.