First arriving units found not one but several units on fire. This is a decent sized trailer park with limited hydrant availability and the main entrance off of route US 40 closed to motor vehicles.Most of the New Castle County volunteer companies were here operating at this blaze and or provided a fire station fill-in/cover-up during this event. One fire fighter injury was reported at this multi-alarm fire. This location has been known for a series of trailer fires,trash fires, etc. just recently. The Delaware State Fire Marshall's office is conducting an investigation for the cause.