Fire investigators are trying to figure out what started a fire at an 18-wheeler repair business in north Houston.

It started just after 2 a.m. Thursday morning.

When firefighters arrived at the facility on Patton and Fulton, they saw smoke pouring from the building.

Inside the facility, extension cords and rags were on fire.

Firefighters were able to put it out quickly.

The cause of the fire is under investigation.