mosty black in color, flew over very low [300 to 400 ft] back and forth. It flew over the active units, tank farm and dock area. It spent maybe 30 minutes over the refinery then left. About an hour later it came back. Same thing. Flew low over the entire area. Was also flying very slow. It was a large helicopter not one of those two seater bubble type.

A couple hours later a refinery safety man came by us and he didn't even know what it was all about. WTF?

Isn't there some sort of "no fly zone" over and around oil refineries now? You would think that some kind of action would have taken place on the part of the refinery but they seemed nonchalant about it. Maybe I'll hear more about it tomorrow.

Was a little spooky tho.

BTW, it had no markings such as a news copter or medical or CG.

Next time that happens call the police and your local NG base, coast guard, the FBI, etc.

Just start shooting at it. You'll soon find out who owns that helicopter. I promise.

Seriously, maybe it was owned by the oil company executives surveying their refinery from above. They didn't clear it with anyone because they wanted it to be a suprise.  

Did it have a turret beneath its chin, like this?

Theres a helo pad at the refinery, not far from where we were working. It did not take off from there nor did it land there.

Someone doing their "due diligence" prior to the sale of your refinery?

Isn't there some sort of "no fly zone" over and around oil refineries now?

No.

There are all sorts of flight restrictions out there, some permanent, some temporary but there is no "blanket" restrictions for oil refineries.

 Right after KATRINA we were rebuilding an electrical substation in Chalmette , La.  It was
adjacent to the EXXON -MOBIL refinery there .  Every freaking helicopter known to man flew over that place ALL DAY , EVERY DAY .  It obviously wasn't a no-fly zone .  I really doubt that
it was something sinister .        Did you see a " N" number on the tail ?