It would appear to be common sense that people would not celebrate the 4th of July, or any other way in the forest, by shooting off fireworks or other 'explosive devices.' From the Bureau release Friday June 1st:

Effective June 1, 2018, the Bureau of Land Management (BLM) prohibits the use of fireworks, target shooting with exploding targets, and the firing of a tracer or incendiary device on all BLM-managed public lands throughout Oregon and Washington. The ban will be in effect from June 1, to October 20, 2018.

But apparently because people do, the Bureau of Land Management (Feds) have officially banned any and all such items through October 20th on Federal lands. Now, these are DIFFERENT from state campgrounds. You will need to check with officials where you are going to restrictions.

These areas include:

Columbia River Gorge National Scenic Area
Deschutes and Ochoco National Forests
Fremont-Winema National Forest
Malheur National Forest
Mt. Hood National Forest
Rogue River-Siskiyou National Forest
Siuslaw National Forest
Umatilla National Forest
Umpqua National Forest
Wallowa-Whitman National Forest
Willamette National Forest 

Washington Camping Areas by Forest

Colville National Forest
Gifford Pinchot National Forest
Mt. Baker-Snoqualmie National Forest
Okanogan & Wenatchee National Forests
Olympic National Forest

These are places you will run afoul of the law if you set anything off. So, be smart when camping and recreating!