Police are investigating an explosion and fire at Barry-based M&G Haulage.
Four trucks and eight containers were destroyed in the blaze which caused more than £100,000 of damage to the company.
Managing director Michelle Goodman says the company has been targeted for the past six weeks. "There has been sabotage going on with cut wires and fuel lines," she says.
The fire started on a vehicle at about 1pm on March 11 and spread to the truck's fuel tank, causing the explosion. The blaze then spread to a further three trucks.
Police are treating the incident as suspicious.
M&G Haulage runs 26 vehicles at the Atlantic Trading Estate at Barry Dock.