The fire has been burning in the Salt River Bed near 91st Avenue and Southern since Sunday.
It's not far from the Loop 101 in Tolleson.
The fire sent a column of thick smoke in the air that could be seen for miles.
Fire crews from the Bureau of Land Management say the fire kicked back up Monday afternoon.
No structures are threatened at this time, and officials have no word yet on how the fire started.
Officials say up to 70 people could be working at the scene on Tuesday.