MCAS is a blimp facility. We don't use blimps in the military anymore. I think they used Tustin for helicopters, too.
Nearby El Toro MCAS had jets, until closed recently.
They can expect to find solvents in the soils. I expect they will mitigate, by replacing and/or somehow treating the soil.
Near Sacremento there was a military site where space travel jet engines were tested. Rancho Cordoba, I seem to recall.
They washed down the engines with harmful solvents, which leached down and got into the aquifer, making the water unsuitable for use.
I worked for an engineering company which worked on mitigating that problem.
Orange County (Tustin and El Tore) has extensive ground water sources, and similar damage is at least a potential. No doubt, these two sites have been studied and tested extensively.
The risks should be well known.
Since WWII until present, Orange County has grown from under 200,000 to over 3,000,000. Not the best place anymore, for military bases.
In the mid-1960s, Tustin was a nesting place for Marine UH-34s. And a laid back duty station where brass was mostly non-existent other than in your M-14 or M-60.
Pix of UH-34s at work -
http://www.aviationartbydubose.com/uh34.html
You may be referring to the old Aerojet site, near Rancho Cordova in Sacramento. That clean-up went on for quite a while. (I admire the rugged individualism of your spelling.) That picture looked like a blimp hangar; I grew up near Akron, where the Goodyear blimp lived, and as a child, went on school tours of the blimp hangar. Rumor was, it was so tall, it would rain inside when the condensation got too high.
Oh MCAS LTA (Lighter Than Air)
We don't use blimps in the military anymore.
That is about to change.