Although the official cause has not been determined, witnesses say the fires began soon after a large freight train passed through the area. As many as five fires burned on both sides of Cellars Avenue and both sides of the tracks.
"I looked out my kitchen window and geez, a big, a really big fireball, then we started hearing explosions, it was just really scary," witness Marilyn Stacy said.
"I was coming home from work and I saw the train going by and it was on fire and it just kept going and then by the time I got home it was already a fire here," witness Trinidad Dias said.
A barn, several small out-buildings and some heavy equipment caught fire and a large plume of smoke could be seen for miles. Due to concrens about the smoke, a shelter in place was ordered for the town of Knightsen and Knightsen School was evacuated. The shelter in place was lifted just after 5 p.m.
Several passenger trains that regularly pass through the area experienced delays.
Contra Costa County firefighters and crews from CAL FIRE responded to the fire and remained at the scene well into the evening to watch for hot spots. No injuries have been reported.