force base east of interstate 80. the crews were called just after 1:00 this afternoon. thick, black smoke as you see, well that could be seen from sacramento, livermore, and san francisco. neighbors who live within a mile of those flames were told stay inside. robert lyles on what investigators think started it all. robert. reporter: just the past 30 minutes, that large platoon of firefighters disbanded, but they are still on scene as i step out of the way. that s evidence by that ladder truck that is still extended above a one story high pile of molten plastic. firefighters tell us what burned here was much more than produce crates. instead they describe it as gasoline in solid form. so they say that s why when a worker torched one crate, five acres of crates went up like a golden inferno. and you re about to learn why water pressure allowed this fire to grow out of control. how do you fight something that is effectively solid gasoline? it s very difficult. it s bee