Officers are appealing for information after being called to Castlefield Street, Shelton, on December 3 at around 9.40pm following reports of deliberate ignition of cars.
It is reported a number of cars were set alight at a scrap yard with the fire having been started in a plastic skip.
A 48-year-old man was treated at the scene for minor burns by ambulance staff. Staffordshire Fire and Rescue Service also attended the incident.
Anyone with any information or CCTV footage that could help the police with their enquiries, is asked to message Staffordshire Police on Facebook or Twitter quoting incident number 714 of December 3, call 101 or alternatively contact Crimestoppers anonymously on 0800 555 111.