They state the following:

 Because some vaccines contain aluminum, the FDA published a paper in 2011 (Mitkus et al.) to address concerns about aluminum exposure from vaccines in infants. The paper compared the aluminum exposure from vaccines in infants to a safety limit of oral aluminum determined by the ATSDR. However, this study incorrectly based its calculations on 0.78% of oral aluminum being absorbed into the bloodstream rather than the value of 0.1% used by the ATSDR in its computations. As a result, the FDA paper assumed that nearly 8 (0.78%/0.1%) times more aluminum can safely enter the bloodstream, and this led the authors to incorrectly conclude that aluminum exposure from vaccines was well below the safety limit.