http://georgewashington2.blogspot.com/2008/08/16-labs-had-killer-anthrax...

Page 6 of the FBI's search warrant affidavit in the Ivins' investigation states:

"Of the sixteen domestic government, commercial, and university laboratories that virulent RMR-1029 Ames strain Bacillus antrhracis material in their inventory prior to the attacks. ...."

As the Baltimore Sun summarizes it:

"The government said that 16 government, commercial and university labs had the strain of anthrax with the same genetic mutations as the anthrax used in the attacks.

***

And even at Fort Detrick, the government said that more than 100 people had access to the flask, creating a lot of room for reasonable doubt."

According to the Washington Post, the other labs obtained the RMR-1029 from Ivins:

"The FBI determined that Ivins had shared samples of his RMR-1029 bacteria with as many as 15 other labs and institutes nationwide."