A semi-truck caught fire on Monday at a transportation business outside Pasco. The truck was fully involved in the parking lot of the business at 7223 Railroad Ave. around 8:30 a.m., according to Franklin County Fire District 3. It appears the truck was empty with no trailer attached when it caught fire after being parked in the lot. The exact time the truck was parked is unclear. The truck was a total loss, but no other damage or injuries were reported. Chief Mike Harris said the employees at the business called 911 when they noticed the fire. They tried to reach out to the person who last drove the truck but were unsuccessful. Investigators say the cause was most likely a mechanical issue. The cause of the fire was not determined.