Three employees at Grade A Auto Parts and Recycling are still unaccounted for after a UPS cargo plane crashed into Louisville business.

The cockpit voice recorder captured a persistent bell that began about 37 seconds after the crew called for takeoff thrust, and the bell continued until the recording ended, an NTSB official said.

Witnesses who felt the flames from a massive explosion after a UPS cargo plane crashed near the Louisville airport describe a hellish scene. CBS News' Tom Hanson reports.

In the video shared by the NTSB, a path of destruction and charred buildings and cars is all that remains following the deadly plane crash. The incident killed at least 13 people, including one child and three UPS crew members who were aboard the plane.