Criminals also attacked the depot office on the Rayleigh site but attempts to start a fire in the building caused only minor damage. Essex police are treating the incident - which happened on Saturday 29 August as arson.
Biffa believes the damage was caused in order to deliberately limit its operational capability.
A Biffa spokesperson said: We expect to write off some of the trucks as the cost of repair will be uneconomic and the office needs some repair work before it can be brought back into full use. However, we have replaced the fire damaged vehicles from within our fleet.
Essex Fire initially sent out two engines to tackle the blaze but another two joined them after the incident officer requested further support. Fire-fighters managed to extinguish the fire just two hours after it was reported.
The waste firm believes arsonists accessed the depot through the adjoining premises by cutting a hole through security fencing before starting a number of fires.