Notorious anti-vaccine advocate David Geier has begun working at the US Department of Health and Human Services and is seeking access to sensitive vaccine safety data that the Centers for Disease Control and Prevention had previously barred him from accessing—at least twice—according to reporting from The Wall Street Journal.

Geier and his father, Mark Geier, who died in March, are known for peddling the thoroughly debunked falsehood that vaccines cause autism, publishing a long list of dubious articles in low-quality journals that push the idea. In particular, the two have blamed the mercury-containing vaccine preservative, thimerosal, despite numerous studies finding no link. Thimerosal was largely abandoned from vaccine formulations in 2001 out of an abundance of caution.