SAN ANTONIO -

The driver of an 18-wheeler was not hurt Friday after his big rig exploded into flames on the city's Northwest side.

The incident happened around 6:45 a.m. Friday near Les Harrison.

A viewer said they saw the big rig's cab on fire.

The driver of the truck was heading east on Culebra when smoke began rising from the engine. The driver stopped and that's when flames began shooting out, officials say.

The fire spread to the cab and burned a fuel line, causing 20 gallons of diesel to spill out onto the road.

A hazardous materials crew was able to contain the fuel to the roadway and clean it up.

There were no reports of any injuries.