George Washington’s Blog 
Friday, Aug 8, 2008
It is clear that hundreds of people  had access to the specific “RMR-1029” batch of anthrax stored at Fort Detrick (where Dr. Ivins worked) and used in the anthrax attacks.
What is less well known is that the anthrax was probably not manufactured by Ivins or Fort Detrick. Instead, it probably came from the Dugway Proving Ground in Utah:
“Called RMR-1029, it was also referred to by Ivins as “Dugway Ames spores – 1997,” apparently from its original point of manufacture, at Dugway Proving Ground in Utah, an Army biodefense center administered by a company called Battelle .”
Scores of scientists work at Dugway Proving Ground, and the Army Reserve, National Guard and Air Force also operate there :
In addition, Dugway’s mission is to test US and Allied biological and chemical weapon defense systems in a secure and isolated environment. DPG also serves as a facility for US Army Reserve and US National Guard maneuver training, and US Air Force flight tests. DPG is controlled by the U.S. Army Test and Evaluation Command (ATEC).
(Article continues below)
Given that RMR-1029 likely originated at Dugway Proving Ground, isn’t it likely that the originator of the sample kept a sample himself?
And given that many hundreds of people from various branches of the military work at Dugway, isn’t it possible that one of them could have stolen some of the sample? Obviously, biological agents would have been kept under security. However, my point is that this was not solely a bioweapon facility, but also a military base. High-level brass could have authorized entry for others, or someone who worked at the lab could have been bribed.
Indeed, like Dr. Philip Zack – a Fort Detrick scientist who gained access to the anthrax lab even though he no longer worked there  – someone could have talked their way into the Dugway bioweapons lab.
Update: The New York Times states :
“The attack strain contained bacteria with both the flipped and the unflipped DNA, showing that it was a mixture of two strains, which analysts later found reflected a mix of origins — 85 percent from the Dugway Proving Ground of the Army in Utah and 15 percent added at Fort Detrick, according to one person close to the investigation.”
This confirms that Dugway was the origin of the bulk of the anthrax. The “normal” Ft. Detrick Ames strain was fairly common before 9/11 , so many people could have obtained samples and mixed them into the Dugway strain.