The man is believed to have sustained the injuries while uncoupling a trailer which set alight in Wednesbury.
The blaze, which happened in Hallens Drive, on Wednesday afternoon, caused the road to close.
A spokesman for West Midlands Fire Service said: "We received a call at 4.10pm to an incident involving one lorry trailer fully involved in a fire.
"The road was temporarily closed by firefighters.
"One man suffered minor burns while unloading the trailer from the lorry."
Photographs published on social media showed large plumes of smoke rising into the sky and a blackened trailer.