fogging

Check the camera for light leaks with a film holder in the back. Once you have ruled out the camera then install each film holder with the darkslide removed and check the darkslide light trap for leaks.
Are there any shinny spots or screws on the back side of the front standard or lens board? If so paint them flat black.
Does this occur on smoggy/hazy days or clear days?

If light is leaking into the camera and fogging film, it will also leak out. Procure as small bright flashlight. Any will do but a Min Maglite or equivalent work best because you can unscrew the reflector and it becomes la bare bulb candle light. Insert the operating flashlight in the interior of the camera. Move to a total darkness area. If the camera is not light tight, you will see light spilling out. Sometimes camera light leaks are difficult to spot. This technique works however if the light leak is trivial you might need to dark-adapt to see it. What I am saying is, sit with camera in a darkened room for 10 or 15 minutes. Rotate the camera so you are looking at every seam and crease in the bellows and film holder area. If there is a light leak, you will find it using this technique.

I did a light leak inspection of the bellows, lens board, and film board, and all seems tight. I did two exposures (each of different EVs) of a white board, then two with no shutter just removed the film slides, and one film straight out of the box. I then developed all together in D76 for 7 minutes. The film out of the box and the two from camera without shutter exposure came out clear, however all three do have a slight but definitive density difference from top to bottom at about the middle. The two shutter exposures do have spot fogging more defined at the edges and more noticeable with the lower EV exposure.

Light leak in the developing tank, change bag, or darkroom.
Darkroom test: turn off all lights, cover luminous timers, sit there for 5 minutes then hold your hand 6 inches in front of your face and slowly turn 360 degrees. If you can see your hand, however slight, at any point there is a light leak that can fog film. Fluorescent lights have an after glow that can fog film also.

Like I said I developed 5 sheets of film at the same time and proceedures and etc.. The two fogged sheets were exposed via the normal shutter exposures, then two sheets the shutter was never opened just the slides removed for 30 seconds and came out totally clear, and lastly the one sheet was taken straight of the new pack of film in the Kodak box. All sheets and chems are fresh. Guess I need an expert to figure this one out.

The film out of the box and the two from camera without shutter exposure came out clear, however all three do have a slight but definitive density difference from top to bottom at about the middle.

2 sheets that were loaded into a film holder or 2 film holders? + the 1 straight from the box=
darkroom, change bag, processing tank light leak. Wrong 3? specify more clearly, please.

Are you using a change bag or tent? yes=is the elastic around the arm sleeves fitting snugly on your arms? Loose fitting arm sleeves will leak light.
Does the fogging extend to the film edge or is it just within the image area?
Can you post a scan of the defect?

Assuming you are correct and the fog is applied as the shutter clicks, it's fixable. Take off the back and looking into the camera from the back, snap the shutter open "B" or "T" setting. Point at bright light, point at brightly illuminated white paper. Look for internal reflections. Snap the shutter using the slowest shutter speeds. Look at the shutter blades, do they stick, hastate, fail to uniformly open or close? Does the shutter leak light? As you, examine the interior with the shutter open, wave about, inside the camera a white paper wand. Place it against the inside of the bellows; you are looking for stray light. You may need to work under a hood to exclude ambient light so you can properly inspect the camera's interior.

Alan, I'll try checking the lenses, it happens on my 150mm and 210mm so I'll also check my 90mm. I know it's not what Charles has been thinking because it only happens to film exposed through a normal shutter exposure. I have had and used this camera for over 15 years but all of a sudden it or should I say after moving to Arizona the fogging occured. I will try to attach scan of what I'm talking about, which is more pronounced on the lesser exposed negs.

Looking at your attached image I refer back to one of my previous questions, how smoggy was it?

Looks like smog density variance to me. It took me a while to figure it out when it first happened to me on 4x5 negatives. Smoggy days sky come out blotchy or streaky or both depending on the smog. Those particles in the air reflect light that the film registers.